I recently switched my rack over to run off of a proportional thermostat- I went ahead and got a Herpstat from www.spyderrobotics.com.

I had a few questions over email after the sale, and Dion, the owner, was very prompt and extremely helpful.

I ordered the t-stat on a wednesday, and it was here that friday. Awesome product, awesome service.

So get one for your own rack, DIRECT from the guy who builds them himself. A few people here and there sell them also, but all they do is play middleman and drop ship the tstats from Dion anyway.

I haven't run a helix, which is a little more expensive, but the Herpstat is still a world away from the on/off thermostat I had before.