I have several different rack setups. Just to name a few I have RBI, boaphile, boamaster, ap, ars, and freedom breeder racks. And everyone of the t-stats are set to a different setting. All my probes sit right on the heat tape so you know the temp of the tape, but I have seperate thermometers for in the tubs. I also use a temp gun to check on the temps in the tubs. I use mostly Helix but my freedom breeder cb 70 rack has a Ranco t-stat that is set to 108 and on the hot spot in the tubs it is 92 to 94 and temp on the cool side is always around 78. That is just an example you have to check your own tubs and determine what temps you need to set it at. The heat tape not touching the tub is fine, my RBI racks the heat tape doesn't come into direct contact with the tubs. So don't worry about your settings on the t-stat just your temps in the tubs. good luck
Josh