I want some answers to these same questions. My incubator I built swings from 87-90 even though it is set at 88. It hits 87 for a very short time and stays at 90 for a long time. takes about 45 min or so to drop from 90 to 87 and the heat kick back on then 15 to get back to the 90.

I also think my bottem bin is about 1-2 degrees cooler then the top one at all times. will this realy be that bad for the incubation?? I'll be with in everyones specs for incubation, but I'll have a 2-3 degree swing every hour....