Sorry, I didn't realize I was being asked questions! I really need to subscribe to this thread! I know I PM'd you already, but I'll put it on here in case anyone else noticed that picture.
I didn't have a rivet gun so I ordered the flexwatt from Reptile Basics wired in 1 foot sections. I cut the plugs off all but one then soldered them together in a chain. Next time I'm probably going to try and rivet them together myself, it will be a lot cleaner than what I had to do.
My tubs pull out the front, but you could pull them out from the side too. The screws might be a pain if it's tight, also the window shims will have to be put in differently if your tubs are tight. The flexwatt will get rubbed enough to shock you if you have them tight, been there done that.