I'm using straight Perlite without the grate, and have a clutch due to hatch in about a week to ten days from now. I've had no issues, I just mixed it so that it was slightly moist to the touch, put Press & Seal on and popped the lid on.

Bought 4 cubic feet of it from a local nursery after seeing that this is how Albey incubates when I visited him. Figured if it works for him, there's no reason I can't use the same method. I have the lighting grate (stored in a closet), and haven't had to use it.