I think SubZero and Monk9022 hit the nail on the head. Put your hatchrite in dry, and put a few gallon jugs of water in as well. Then when you're ready to add water to the hatchrite, use the water in the incubator. It'll be at the proper temp already.

That being said, I have mine running with the tubs set up, complete with perlite and water mixture. But I'm using substrateless incubation with egg crate above the substrate.

Steve