I don't know what part of CA you are in SoCa, but 105 degrees is hot in the summer for a greenhouse. I have a 20 x 30 and it gets hot in there and I live in OC a few miles from the beach. That is one big greenhouse and just so you know, I had to get a permit to build mine. Depending on your fan placement you may get enough air movement inside to keep it cool. I agree with whoever said it the lowering of the sides is the critical part to keeping the GH cool or creating a draft by opening up the sides a bit. I have 2 12 in Schafer fans in my GH and you can definitely feel the breeze. The fans really help out with the high humidity here. On the downside of openness, people can see what you are doing and so be prepared for invaders/rippers. On your water well the biggest thing is not if it works but your water quality. Have the water tested before you use it. Also check with your county permitting agency (the ones who permitted the use of the well) to see what the well can be used for irrigation, drinking, etc. Also check out the sustainable flow for the well. Since we are in drought conditions, if the water levels drop, your pump may be below the water level. Check current water levels and the rate of water level drop. Keep us posted.