I used to run bigger squads, then there was too much sitting around between shooting so now I run 5-7 person squads. We start at 9 and done by 1 - usually just 7-8 stages.
Squads RO for themselves, I select a squad leader who's most experienced and he keeps the squad moving. Assignment to squads is a good mix of new shooters and experienced once as mentioned before. Scoring on tablets and we coach every new person to keep score, time and spot so next time they show up, they're up on what's going on..
Ours are sanctioned matches by the club, so the rules are more relaxed on having dedicated RO on each stage
Before running my own matches, i shot a lot at different clubs and took notes and even then it was intimidating to be a MD and try to have things run smoothly.
Over time i adjusted and listened to shooters on how to improve the process - and we made changes for the better.
If there are 8 stages but four squads I'll spread them out so there is a empty stage between each squad so there isn't sitting around and waiting for the slow squad to get done.
In regards to Rimfire matches - shooters bring their kids and spouses to shoot these matches so sometimes you have to be accommodating and allow extra time, this the gap between squads.
I'm at the range at 6am and usually don't leave until around 4pm after clean up. Then still get home, unpack, put shit away, upload scores and update our own season standings....
But it's what we do....