Aftermarket Seat Heaters

I have installed aftermarket seat heaters in my 65 Corvette. The system uses one seat base and one seat back element. They are identical. It has low and high heat settings. The high setting putd the elements in parallel. Low setting puts the elements in series. I would like to be able to turn off the seat base element to provide seat back heating only. NO problem on high, just cut off the base element. But that wont work for the low setting. What I decided to do it use a double throw single contact on/on switch. One side would use the heating element, heat both base and back, and the other would use a resister in place the base element. The heating elements are about 8 ohms so I purchased a 7.5 ohm 50 W resistor. Will this work? Is the resistor wattage high enough? Thanks Tom