I recently let a 4500gram monster mama maternally incubated her 17 eggs in a 40gallon breeder - i now got 14 hatchlings with almost all em out of their 1st shed
i used cling wrap not cardboard, scotched tape it down to cover all the screen except for the screen under/around the heat lamp
~1/3 the area of the tank was water, used 2 pyrex rectangular for that with the heat lamp directly over one
reptile humidity gauges IME are not reliable, i use 2 humidity Digital monitors different make/model - and keep them close to her coz the humidity will vary across the tank - believe it or not the humidity right beside the water is actually lower than the other side
good luck - maternal incubation rocks I've done it artificially but won't again
