The kickstarter for Element Class Cruisers included some guidance on running military active duty campaigns and it included the first adventure, which I think may have a flavour that would cover maybe the 'high' side, but also maybe some 'low' side. There are other adventures, but I have not purchased those yet.
I am going to do a write up for a miniatures war game I ran maybe 10-12 years ago that featured a CO and XO off board and two teams on board with their own commanders (subordinate to the off-board commanders) in a scenario that was complex (had a couple of concurrent operations running on two seperate tables joined by bridges). The player count was I think 9 or possibly 10 including the CO and XO and each table had 3 or 4 players. There were 2 referees plus a tech/assistant ref.
The purpose of the event was to expose gamers who haven't had military experience to:
a) For commanders, the information they have is always dated, often unclear, sometimes contradictory, and orders they give cannot micro manage (bad things happen) but have to also exert central direction.
b) For players, getting orders from multiple higher levels of command that may be dated or just misguided based on HQs misapprehensions about what's actually going on, and also the man-on-the-ground (or woman) may have a better ability to determine course of actions, but they are ORDERS after all... and when do you write your own?
c) Scenarios with particular plans are lovely - like a work of art. Then life happens and your great work is doused in gasoline, lit on fire, and kicked out the 40th story window. How well does your plan allow subordinates to deal with fast evolving situations?
d) How do you (at any level) make decisions in an environment where i) some info is not available, ii) some info is stale, iii) some information can be incorrect (or correct from a certain point of view) and where you do not have the luxury of NOT making a decision...? This is the art of military decision making. You have to act, but you have to do that knowing you don't have all the facts, the consequences of screw ups can be bad, and that your plan can be entirely wrecked by enemy action.
e) To be in a scenario where the changes were fast and furious and that included redefinition of mission goals in mid-game on the fly.
f) To let the out of room CO and XO get information only via a Teamspeak radio channel and by camera shots brought to their room (drone footage)... and to also have them bothered regularly by higher level command and political influences.
We did a 45 minute pre-brief, a 30 minute or so post-mission debrief, and the 3 or so hours in between started out organized and on-plan and then things went south. Despite being connected by bridges, the actors on each table were so engaged with their own struggle and the communications and coordination that they had sparse information about the other side's mission progress. What was very different was one board was calm and professional and the other side was in a knock-down dragout where a loss meant the neighborhood going up to 10K degrees.
Part of the reason the first board's team was calm was: Phil Pournelle (Jerry Pournelle's son, at the time, a Lt. Cdr in USN and XO of the Jervis Bay trimaran class ship the USN had borrowed for testing (and ended up heavily tasked during the Katrina response - from Texas to New Orleans, taking on supplies and distributing them from the Gulf to the harbour, getting stuff put on and off from piers, aircraft carriers, other ships, and helos, and going up the river because of low draught so they could run a damage assessment) - Phil was the on-board commander of one of table (the calm one). He intentionally filtered information from higher command coming down and information from lower command going up. In the former case, the fact a WMD was live on the other board was not passed to the troops, so they were not distracted from their snatch operation and were generally calm. His basis for this was: If it is not something the teams on Alpha table (under Phil) could act on, it was not helpful information. They had a mission to execute and that knowledge would not help that. They needed to get in, grab their guy, and run their evac plan.
So, here are some of my suggestions:
1. Players should be very careful to think in the head of whomever they are running (low or high) and the GM should be clear about exactly what they know and do not know because they will NOT know the same things and their view of any operation will be vastly divergent (low vs. high).
2. It is ideal to have someone playing the higher up that is running a given operation. If they can be kept aside and briefed periodically and provide their direction from that... that's the closest thing to the insanity of the real world. If you don't have that luxury, underscore 'bounded knowledge' so that things the players know as the 'other' won't necessarily be known to the others. Make clear (written lists) of what different layers of command know.
3. Others have raised the issue of rank, but I think I agree - you need (to do High) senior staff with decision making power and the view from 10K meters up. For Low, you need lower level platoon commanders or squad leaders to run and an NPC structure above and below them. They will have a very different perspective.
4. Encourage players to take on the roles of the mooks in fights so they get to enjoy that, but then also make them live with the fallout as the direct CO (platoon or squad officer) who has to deal with the injuries, the casualties, etc.
5. Provide a lot of info in a format that they (at various levels) have to figure out and figure out how to report the significance of and note particularly what they communicate up the chain and then be sure to let the High folks only see the communicated parts. If anyone knows something but doesn't send it up, the higher up player activities should not be allowed to operate as if they knew that.
This is sort of a game of multiple personalities.
Also point out that even grunts want to live but if people (even their senior guys) get killed, the military has succession plans and other folk (perhaps a bit more junior) can step in and step up to fill the the empty position.
As GM, you have to be able to keep straight the knowledge by layer of authority and what is particularly not shared or is shared in a way that can be misunderstood or that is just not accurate to what actually happened. Make sure the players and NPCs stay to those bits of knowledge.
How fast do you cut back and forth? Sometimes 30 min or an hour or maybe a whole night or nights. But you do need to regularly do a swap out if the higher level has sent you on an evolving mission.
That's the advice I have now.
Tom B