Here an old picture at the bigining of the construction, now it have a front glass. soon i will post some pics.
i had only 2 small 5V fans but i think 4 would help with this to much heat on the top, but seems makes no diference. The incubator have 80/90cm high (34in). i use a cable with 50W on the back ( i tried all the back and then tried in the back but just starting in the middle and ending in the bottom and solve a little bit but not enough.
i use several digital probing thermometers, and some fish termometers on differente shelfs.
I use the thermostat probe in the middle but i tried in differente spots with no success.