What advice or observations do you have for someone moving into the 1SG position at a HHC BEB?

You will find that your battle will be in getting accountability and participation in all of the mandatory tasks we need to manage. PT tests, urinalysis, mandatory training, and the like. Staff guys are always "too busy" doing "important things".
Your best friend is also your worst enemy.
All those slides the staff is always working on - you have them too. Except yours have things like metrics on them. What I would do is have a by name list of people that were delinquent on things in the footnotes of the slides. I would make the Commander aware that they were there, and make sure he got the notes print out. Then for tact purposes, I would follow his lead on when to bring up the by-name list. It was pretty effective.

1SG Alan Boggs I never had the position, but I was one of the many very senior folks in their "company" at both the BN HHC and DIV HHBN levels.

As the Div G3 SGM, like all the other HQ department leadership folks including the 2 star CG, his 3 one star ADC's, the Div CSM, and many others, we were a PIA for our HHBN 1sgt's ... Readily admitted.

At the Div level, planning, supporting, leveraging, battering, conference calls and Video meetings never stop with outside agencies or units.. SO a UA, is an all day deal, and you have to bring your UA folks to the HQ building and make it as easy as you can for them to comply. SO your set up in at least three areas, HQ command area, general staff area, and HHC company area.
APFT is a three day deal to get 50% of the company done...and you offer it at least quarterly so with luck you will get 95% done over the year.
Yes the HHC company "Commander" is in charge of all on his roster. and you as the ISG, all of the enlisted..but two things to keep in mind, many in your company by rank or position are in a position to ignore the CDR if not legally (Rank) then by duties/ duty position and support of their department head to Skip that HHC formation I need the briefing done, to not go to this months APFT as you need to be in the room when we are doing the VIDCON with the SMA, ect ect ect.
Work with the unit CSM closely they have a vested interest in the HHC being successful and will support the HHC leadership, but there is a lot of extra work for the leadership of a HHC leadership team. Some times you will need to remind the CDR (or yourself) just because you can, does not mean you should. And those that you "command" will need to do the same, in support of you. "Hmm, I could blow off that formation, no one will say squat...but, I can make time for it before the first meeting of the day, so I will" kind of thing.
Meet often with the HQ leadership, listen to their needs as a staff both support and timings considerations of company events.. You will be working company events around their scheduled..it may not be right but it sure is accurate

EDIT, 90% of what I said above is also true at the BDE and BN levels.....

I've been an HHC Commander. I've also been assigned to HHCs almost exclusively since 1997 as a rank and file staff officer, staff primary, BN XO, and BDE DCO. Here is the perpetual challenge: keeping the linkage between what HHC needs and supporting the staff in their work to support the commander. The mission of HHC is that of enabling and readiness. The HHC Command team is not involved in what get gets done Day to day in the staff. The HHC commander isn't going to get their ass chewed over Battle Update Brief slides. This cuts both ways.

Some tips
- you are hard presssed to getting anything done in one shot. You have to offer mandatory training more than once. If you are a BDE HHC, the DIV will invariably unravel your staff support with a no notice hey you t the staff or it's during USR and the S3, Chemo, S4, and S1 won't be able to support your focus area. I had a two times three in the morning rule. I'd offer training, scheduled twice, the third time would be three am on a Saturday. Sometimes the XO will resource a way to do mass training because the issue is also impacting hem or it is a directed thing from higher. Be ready either way.
- The XO/DCO are your point of entry. They have to know what you are doing and obtain their support. Many times, what you are asking for is a stretch for the staff and the XO has to sometimes tell the staff there is no good time for this and the staff just needs to suck it up. There is only so much gas in that tank.
- Army basics like weapons and APFT are hard. You need rotation plans to ferry people and weapons to/from the range. If you make it customer friendly and get XO buy in, you'll get the support. The APFT and weigh ins are through long range coordination.
- buy in from staff primaries (S1, S2, S3, etc and their NCOICs) is important for day to day support. The NCOICs will usually attend your training meetings and bring back the info to the staff. Just understand that in the case of small sections like the UMT and S2 as examples this might be 50% of that section. Generally giving advanced notice is powerful. You have to take seriously things you think are bullshit. The BDE Maintenance Meeting for your Support Operations Section in a Logistics unit is a prime time event and how their success is measured day to day. While it may seem unimportant to the HHC team, thismis the SPO focus. Likewise, the myriad of USR tasks may be done for you after you submit the SORTS and slides, the S1, S4, and S3 are just getting started.
- training the staff. The XO is going to train the staff. Your training is usually centered on common task, readiness, and support you deliver to the staff and commander. HHC is a critical enabler to staff field training like deploying the TOC. You will need to work closely with the S3.
- this is all about developing and maintaining mutually supporting relationships with the staff.
- as I said, staff sections are not the same, you have to be conscious of this when filling details. As a long time staff officer, I frequently wrote off my E4 and below because they were always tasked. Staff sections have to be cognizant of tasking companies in directives and orders because that tasking is a boomerang booger flick when HHC executes it. They are us, seems obvious but not always. Small sections can't be treated like a "Platoon".
- demand attendance at your training meeting. Get XO support. Make your training meeting streamlined and organized. Plug in an agenda item to see what they have going and what they may need.
- motor stables. The XO will,likely crush nuts over support of this. Ensure the unit maintainers are present and ready to support it. I dragged staff sections through broken glass over parts received, not installed. Ensure if thatnis a focus area the following is available without chasing PFC Lickknob on appointment and they have access to tools: the parts received, not installed report; parts; and tools. Ensure they know what I see recoverable and what isn't. Ensure that at the training meeting, focus areas other than vehicles is advertised in advance like CBRNE, Commo, and weapons.
- occasionally staff primaries will want to run their own stuff. Encourage this. If I knew we were heading into a high optempo period, I'd send my folks to the arms room and clean weapons and do PMcS as the SPO, if I knew their annual gauging was coming.
- soldier issues. Ensure the .NCO and Primary know what is happening so they can 1. Support, 2. Not make it worse. If you have a joe or staff officer that is overweight, they can ensure he is there at PT without fail.
- .periodically attend the section admin meetings to get a feel for their activities and challenges. It will be come a platform of opportunity for you to put out your message.
- the HHQ staff has a tremendous impact on your training and activities in way of support available by your staff. Can't say this enough. Division will preach training, PT, etc but their staff will call yours and set your calendar on fire. Especially if the commander needs to brief it personally.
- Command and staff. Resist the temptation to narc out the staff at Command and Staff. The XO is your point of entry. Also, if the XO isn't supportive, the CSM may be the next place you stop. If you've tried this without success, then weigh that risk and roll the dice.
- encourage dialogue.
- your commander needs to make peace with being relegated to having control over himself and burst radius around his desk after 9am each day. He/She will need your counsel more than ever. They will mysteriously only have soldiers when they are broke and in trouble. It's the job. Embrace it. Walk the staff each day and see what they need. If you have friction with anstaff section grab it by the belt and work through it.
- you and your commander will have to use leadership muscles you didn't know you had. It is much more peer leading than positional leadership. Get it right, and you will be very well equipped to handle higher, more nuanced positions later on.