I have built several incubators but I want to build on that is taller, about 48" tall and about 16" wide and 16" deep. Just wide and deep enough to accomodate several of the standard auto turners, one above the other. My question is, should I put the heat source at the bottom and fans blowing down on it to get the air moving or should I put the heat source at the top and blow the air down. If I put the heat on bottom I am afraid that any eggs right above it would get too hot and if I put the heat at the top I am concerned that the eggs toward the bottom would not get enough heat. Should I have mulitple fans, multiple heat sources tied into multiple thermostats? Any suggestions?