I've been struggling with ambient temps in my 20G L glass tank so I picked up a 100W CHE and a 8.5" lamp with a built in dimmer. Is it safe to rest the lamp directly on the screen top or do I need to keep it suspended above the screen top?

The lamp came with a clamp but I don't have anything to clamp it to at the moment. My humidity is really high (70-80) so I'm not too worried about that yet.

This is my first time working with a CHE so any advice is appreciated.

Thanks!