My experience has been best to control the temp of the air going in. I suppose no issue with the saran wrap, but don't forget to leave a way in
. I made a PVC door frame and then cut it out of the reflectix, bought industrial strength velcro, and attached a reflectix door with it.
How much dough you got to spend? I pondered that you could build two tents. An outer one to give a stable room temp and and then the tent itself. It is just that fro.m what i have seen, if you have a good exhaust fan the air is in and out so quickly that relying on something close to the intake isn't enough, it will still pull the overall room temp air in. Anything in the tent is pointless as it gets exhausted too quickly, just a stream of cold air leaving the tent.
don't worry about intake, passive is fine. A hole at the bottom of the tent will allow the exhaust to pull in all you need. That maybe all you had in mind. I didn't get what you meant.
But from my limited experience. In a sealed room with CO2,you can control the temp in it. I have never done this. But with exhaust and intake, I think I would have a hard time managing temps in a garage and that is with LED that add little heat.
Or...find a hidden corner in the house! I cant imagine not being able to open my garage door. Be careful in Texas, y'all suck legallike....