I have about 50 tomato plants that I am planning on trying to force throughout the fall and early Winter - taking it as far as I can. I am constructing a greenhouse out of plastic covers, I'm trying to use whatever lets in the most light combined with heat retention. I will also use floating row covers and low hoop houses as necessary / feasible.

I am also going to put space heater(s) in the greenhouse when it gets really cold.

My question is as follows:

At what temperature and humidity should I maintain the environment, and should I attempt to modify the photoperiod? I'm looking for the best combination of green growing (they're seedlings) and then fruiting. Any advice on forcing tomatoes?