I've seen mega simple incubators work. A wooden box with water resistant paint, a glass window, and a bunch of heat tape on a Herpstat is used by a bigger breeder around here. All it needs is to hold humidity and warmth with a method to control and stabilize the temps. I think Herpstat has a product that controls both heat and humidity.

The only thing to watch out for IMO is that a lot of humidity probes will fail after a while in high humidity (ironic I know). Just keep an eye on it; perhaps have an analog hygrometer for visual comparison.

Ian