Well I did a couple tests. I put a single 11" wide strip of flexwatt down the back of the rack. Unfortunately, the tubs have a lip on them that keeps them from sitting against the flexwatt. I set the proportional tstat at 110 and I still could only get 86-88 in the very rear of the tub. That didnt make me happy. So I went back to my old method of individual pieces of flexwatt for belly heat taped to the shelf. I left the back of the rack open as before, left the connectors hanging over the back of the shelfs so the tubs dont rub on them and slid the tubs in. They arent rubbing and they sit directly on the flexwatt for 90-92 degree belly heat with the tstat set at 93-94. This works well and unless there is some hazard I am unaware of, i will stick with it. The heat rope blows (technical term). Thanks for the input folks!

J