I'm planning on going to two CHEs hooked up to thermostats in the near future. Has anyone had any trouble places these directly on top of screen lids(w/ lights in proper dome)? Also the way the screen lid is set-up (4- 7.5"x16.5" mesh squares divided by plastic) I'm afraid if I don't go directly on top of the screen, elevating them would melt away the plastic in no time. Anyone have any reviews/tips on CHEs as I've had no prior experience? Thanks!