A buddy of mine had his fuel gel during our last cold spell, so he put an aquarium heater in his tractor's diesel tank and set it to the lowest temp (I think 40F?). He said he waited a while until the heater cooled to the fuel's temp before plugging it in, then left it on overnight and by morning the fuel was 40F (or whatever it was set to) and all the wax had been melted back into the diesel.
So...this seems too simple. A 20 dollar heater can solve all of your fuel concerns?
There has to be some reason reason why this is a bad idea. Doesn't there?