Ah, thanks for the reminder. I have been meaning to plant a FD tree outside somewhere in hopes that it will eventually fruit and produce rootstock seeds. I don't have a good place for it yet, I need to think about where to fit it.
My heater kicked on for the first time last week. I have it set to 55F and so far it has been working perfectly and cycling 3 times per hour which is ideal. I installed two ceiling fans in preparation for winter based on your recommendation, and they are fantastic. I feel I don't even need horizontal fans with the ceiling fans running, and they take up no floor space. I have them set to turn on automatically any time the vents are closed.
My greenhouse is now quite crowded as I brought in some herbs and tender perennial flowers, and I have some tomato and pepper plants growing also.