Which one do I get???

I would really recommend against covering more than half of the tank with Flexwatt unless you wire it separately and control it at different temps. Your "hot spot" is supposed to create a heat gradient so that your snake can thermoregulate. Also adding extra heat tape will not raise the ambient air temperature significantly, so if your snake is in a cooler room, the air in the tank will be cool. The way snake anatomy was explained to me, the lungs take up a huge proportion of the snake's body and thus ambient air has a much greater effect on body temp than surface (heat tape) temp. Kind of like sitting on a warm blanket but breathing cold air. Some breeders do prefer back heat to belly heat for this reason. So my point is: I think your snake would be happier with heat tape on 1/3 of the tank (one 11" strip it sounds like) and then a lamp or space heater to adjust ambient temps. Just my $0.02.

I have a Ranco and a JC...what I've noticed about the Ranco is that it really only has a +/- 1 degree swing, and the JC is slightly more.

I like the controls of the Ranco better as well.