I always keep the same number of different sleeping options as there are gliders in the cage - the exception is my large colonies. For colonies of 5 or more, I put only 5 sleeping spaces in.
I only occasionally find them sleeping separate, but it does happen from time to time in almost all of my cages.
I try to offer a wide variety - sleeping pouches, play & stay logs, play & stay hollows, sleeping cubes, sugar combs, monkey cliners, etc.... Without fail, if the option is presented, they all choose to sleep in one of my sleeping cubes. If it is not an option, though, then they will migrate from place to place to sleep, sometimes choosing one for naps during the night and a different for their lengthy day-time sleep.