Have you participated in rotating GMs?

[Duff]

Rotating GMs have been the standars in my 2.5 decades of RGPs over various groups. Generally that works fine.

Rule 1) That would be difficult. You generally don't want to strictly regulate the number of sessions a turn takes if you don't really need to. There are always longer and shorter adventures, there are always GMs miscalculating how long it will take and what the players do will and should effect the duration as well. Guideline is better than rule here.

Rule 2 ) Is fine. Not all our rotating-GM groups had it but many did and it was generally for the better.

Rule 3 ) A little flexibility might be called for. There is always real-life stuff getting in the way. As long as rule 2 is kept and not only in name, it would be enough.

Agreed. Flexibility means the person who turn it is to GM next failing to get their "schedule" together (whether because of life, or because they just aren't that committed) doesn't mean the group folds.
It also means the person who's been struck by inspiration and has a great game ready to go is free to do it. Whereas, by the time their turn comes around their enthusiasm may have waned

Also everyone GMs can be good to have some give in it I say as the member of the group with the most hours of work per week and a sole parent in a group of bachelors.
Some people are also temperamentally unsuited to GMing, Too shy, not able to think on their feet quickly enough, In a group of experienced players, you might want to give the newbie a while to get up to speed before you push


Also, within a campaign, I've played rotating GMs quite successfully. D&D and MechWarrior games where there's an element of turn taking with who runs the next adventure. The things to watch for here are
You need a level of communication about where adventures start and end and what treasure the party gets along the way. If the party has no flight, don't give them flight without checking with the next GM that flight won't wreck their planned adventure.

If the party's marooned on a desert island and you have and adventure to get them off it, say so. Then let anyone who wants to run desert island hijinks the chance to do so before you run your thing


Also, I've always wanted to run a troupe style game like Ars Magica where some or all of the players have "areas" they run stories for. So maybe one player runs the relations with the nearby Baron, another runs the fairy court and a 3rd runs a rival covenant. Another GM might run "everything else" or everything else could be shared more evenly