machnut's post in a nutshell is he has a uni-bit and drills holes with it... tho im not sure why you would need it. I just put 1/4 inch holes in my tubs if they need it.

I use bottom heat on my racks, controlled with a thermostat its not going to get much hotter than what the thermostat is set for. tho i use newpaper so not much to heat through. even if you use bedding it shouldn't got hot enough to harm the plastic.

another note, I've been told by multiple sources that neos respond better to back heat rather than belly heat, mayb its a michigan thing, I don't know, just what i've been told, no personal experience, but herd it enough times, when i do build a baby rack, it will be back heat.