LOL, I've been there and done that also. I'm a huge fan of the 4x4 vehicles.

I did a test run with a 1 inch air gap. It seems to keep things way cooler. I just set a tub on top that was up one inch off the top of my cage (over the hot spot). I will get a little heat up into the upper floor but not as much with a 1 inch space. Plus the PVC cage is thicker than the tub. I'll put like 9 pucks between the 2 cages. 3 rows of 3