Do you rest it on the top of the tank?

My tank is 31.5*14.5 (and most lids/screens are 30*12) so we're making one out of plexiglass with a piano hinge and velcro to keep it down. I'll be drilling ventilation holes but I'm m worried that drilled holes won't be enough to let the heat in and melt the plexi... But, plexi melts at like 160c (320f).

I was also reading that it's advised NOT to use a dome cos it'll trap the heat, and that's why you use the cage lamp so there's lots of circulation. But that means it'll be hotter to compensate for the loss when it's open 360° like that... so they get way hotter. One post I read said she temp gunned it at 400f, which will melt the plexi. I wonder if she was using a dome? At least my dome would have a dimmer on it.

I think I'll keep the bulb for now. They must be tired seeing my face from picking up supplies from fish, axolotl, cat to snakes a few times a week. I would also feel weird returning something I had gotten from a previous return...

I like the words for CHE, being lightless and lasting way longer than bulbs, but it's the oft mentioned heat i'm worried about...