I'm inexperienced at incubation and hatching so I can't help you any except for what I've read/studied. Did you run the turner while you were doing your tests? It doesn't seem like the turner would generate much heat but seems I read *somewhere* that it affected the temperature a bit. Maybe I...
A heat-sink in the incubator would help with stabilizing the temperature...bottle of water, a few large rocks, etc.,. If you were to use a bottle, you could use a baby bottle and run the probe of a thermometer into the bottle through the nipple to get an internal "egg" temperature. I would...