I can put it on cinder blocks and buy the 2.5x2.5 when I can afford it, maybe do half at a time like I was anyway.
The roommate thing I guess wont be a problem I can explain it will be fine. I just have my set space and if it fits, it fits, and this will be in the existing flower tent so should be fine.
I want to figure out asap as tent is empty and need to figure out a solid long lasting system and if you think it will work them great. Il do that. I would hate to find more problems with my initial idea.
A bonus is I can run whatever I want in there, not necissarily 8 plants.
Figure out what tray will fit in your space.
Buy the tray that will fit in your space and will do the job you want it to do.
Buy once, cry once. If you continue down the path of trying to save nickels and dimes, you will spend much more money in the long run than if you were to buy the purpose made part to begin with. Trust me. I have tried saving a few bucks here and there. When it comes to the tray, get the right one. If you have a local shop, stop by and talk to them. Ask if they stock one. If not, they should order one for you. The freight charges to ship trays are ridiculous. If the shop orders it, you can save a pretty penny. Believe me when I say, the tray is worth the dumb price tag for the convenience it brings. I am running a 3x3 in my 4x4 tent and it is working beautifully for my purposes. You can run a condensate pump to empty it or you can elevate the tray, drill a hole, install a bulkhead and plumb it to drain to a drain if you'd prefer. Either way will work just fine.
Lots of people continue to give you solid advice on here and you seem to dance around the answers and talk yourself into finding a way out of the suggestions made. Look at some of the other people's grow journals and check out their setups, study the setups, ask specific questions about their setups. Don't try to reinvent the wheel.