Expanded PVC Rack Plans

I've been looking for some rack plans to build and found these on kingsnake. I dont know if these have been posted before, but they looked extremely simple and I think the expanded pvc makes it look professional. I was just wondering how you would prefer putting flexwatt on it?

Heres the link with step by step pictures, hope this is ok:
http://www.northeastsnakes.com/racks.htm

I would probably zig zag it across the back of the shelves for the hot spot provided the tubs bottom don't rest on them (ya might need a router). LOL The plans are really good.

Yeah, I figured you could just router the pvc, as he said it was workable like wood. What about back heat, and what type of material would you use to back the flexwatt if any.

You can zig zag the flexwatt throughout the rack and put foil tape over it to protect it from the tubs sliding. If you dont want to use the foil tape then you have to router the slot.. Back heat works great for smaller tubs but is really inefficent for larger tubs...