This is my first time starting a perpetual harvest, so far I have not entered any new flowering females into the flowering tent. As of now, I see that 4-6 of the 11 I have now are goin to be done sooner than the rest, White Widow and White Rhino finish before the more dominant sativa bag seeds I grew. I am however feeding these females in conjunction with vegging mothers and clones. That is already 3 seperate feeding schedules plus a 4th once half the females start needing overdrive nutes and final flushes. I use advanced nutrients so it is pretty simple since they auto PH themselves. Just measure what PPM you want to give and add to your clean water. I am not a FanBoy of AN but I have limited experience with too many brands. I have only used General Hydro for my first grow and then I jumped to Advanced Nutrients. Their prices are pretty good except for Voodoo Juice. I just started using Great White Mycorrhizae and House & Garden Root Excelerater instead of Voodoo.
So far it has been pretty simple, I timed my waterings so that they are all done on the same day, (except clones). This makes it so I only have to spend one night watering my girls. The rest of the nights I am just checking on them for about an hour. The best tip I could give you is to take great notes, keep a calander where you keep track of every tent/grow chamber and a log book or note pad where you keep track of your feeding dosages. I like doing it so it doesn't really bug me. If you aren't that into it I don't suggest doing it cuz it will be more work than doing a single grow at a time. Hope this helps bro.
We will see how it goes.