Think of the incubator as a heat source only. The humidity it holds and heat mean absolutely nothing other then getting to the correct temperature. What matters are the tubs and the eggs. Sealed tubs are the only way period. What did you use for incubating? Vermiculite, perlite, diffuser, etc....? What were your temps and were they consistent or did they fluctuate? Did you take temps of the eggs? Incubator temp and egg temps are different.
What temps did you keep your snakes at during the breeding season?