one thing i noticed: i would position the fans differently, so that the whole air inside will be rotating. if you put both in the back, the air in the back will move down and the air in the front will move up. but you have one in the back on the left side and one in the opposite corner, so further down in the incubator they might be cancelling each other out. maybe it will be better if you move one, so that both are in the back, you should give it a try.
Thanks for the tips, but I'm quite happy with the air flow and temp distribution in the incubator ATM.