Random thoughts while on my second err third vodka.
I think I'm going to just prime and paint the OSB floor. I don't see how it would be less waterproof than with added vinyl planks, and it saves me about $1000. I don't want it to look too nice anyway, because my wife still wants to put a library up there. I told her I would make space for her library when she made space in the living room for a grow tent.
Still not sure how I'm going to make the access doors. I have no experience with this kind of door, and I don't want them to start sagging or falling apart in a year. Or worse, leak and screw up the heat and A/C. Seems like fence gate hinges and 1/4" finished plywood is my best bet.
Reminds me I need to put in an A/C exhaust vent for the portable A/C I plan to use. I guess I should have done that before the drywall, LOL. I need to put it somewhere the HOA can't see it, too. That's going to be the wall behind the door in the stairwell. I think that $1000 I might save on the floor is about to get wasted on A/C duct work.
Spider Farmer has a 5 X 10 tent that looks really nice. Vivosun has a 5 X 12 that would be better, but their zippers suck. I could get a 6' wide tent in there as long as it was under 80" tall, but I don't see any for sale. Two 6 X 10's would just about fill the available space with a little left over for seedlings and clones. Considering the laws in my state, I must be nuts : )