I just got a johnson thermostat control for 60 bucks ( new) and I loving it . It will run all 17 ft of flexwatt with no problems. I got another friend checking on the pricing for a second one for my next rack I hope to build this summer.
I find it a bit of a pain to wire up with a 3 prong cord but I cheated and used my electronics schooling and instead of triyng to stuff the wires though the little hole .I just made a fancy pig tails and solder them in place then tapped it up. This way all I had to do is run my connections and it all set and nice and strong too since all contact are tinned and trimmedto fin inside their plug hold.. I then taped along the lower botten of the unit the cord to take any strain from the cords weight ..