adjustable is nice I suppose when you're trying to tune where you want it, but if you're going back to street driving, I imagine you'll be setting it and forgetting it.

all you need is a relay from the junk yard. for example, Dakota's have a relay on the inner fender for the Fog lights, if the truck has fogs.

then use a grounding sending unit to ground the control circuit of the relay. you can buy just the sending unit for around $30-40 and there are lots of options available. I have a 180 degree stat and found a sender that's 195 on, 185 off. Then I was really sly and wired it into a spare slot in the factory power distribution box on my Dakota, so that it looks factory and I don't have an extra relay bolted to the side of my inner fender.