Yes, and I'm not sure the 70 degrees will be enough without an insulation enclosure on the tanks too.
I bought the seat heater on ebay and it shipped from China.
Seat HeaterThe question I asked was did the heater include 2 SETS and one control, i.e. for two seats. The answer was yes, but the language was an issue--so I asked them to update their site, and they did! It is now much clearer that you are getting a set of two pads for one seat.
But for my trouble, they sent me a second set.
It is not obvious, but the switch on this set is not only is variable for temperature (the 70 degrees was on HIGH), but it also turns off the heater. It does not come with any wiring diagrams etc. but the three color leads are for three different functions, ON is red, and yellow and green are the amber and green lights that show the switch has power or that it is on. I tried to put another switch on the system until I found an explanation of the wiring online.
I'm currently waiting for the motorcycle handlebar heaters for the valves. I bought those from amazon, but it is another China supplier. Cost was something like $4.62 with shipping though.