I'm been researching a lot and reading through the posts about flex watt. We get the keys to our house on friday and I plan to build a rack system within the next few weeks. I found the Melamine shelving in the size I want, long enough to hold four 6qt tubs. I plan to get enough flex watt to cover the shelf. I understand all the wiring and what not, but my question is.....

Once I get more snakes and need a second shelf for tubs and step up another flex watt system do I need two thermostats?

And how do you know all of your tubs are heated equally? Or do the flex watts do a really good job of distributing the heat?