I have 3 good size moms in 2.4 gal airpots in a 2x4x5 tent and its a full house. Id upgrade it to a 4x4 if I had anymore floor space in my lung room.
Try it out but I dont see it working for a perpetual with clones rooting in it too. I mean a tray and dome is 10"x20" so thats a huge chunk of your floor space. And 40 cuttings at a time you will want to use 2 trays/domes trust me. So thats 20"x20" of your 36"x36" tent used up. I would build a small clone box out of wood and polly or even a rubbermaid tote, or buy a dp90 tent. I prefer a clean look so I got the dp90 it fits three 10x20 trays/domes perfectly. Its was only like $90