If you want to control the speed going downhill, use the cruise control first. It will keep the car at the set speed and by holding it back generates power to charge the battery. Use the brakes mainly when you want to slow down more quickly. I live in the mountains and I do that all the time. I also coast whenever I can and that still generates power although not so quickly as using cruise control or braking. On long hills, the battery often gets fully charged and the engine starts and downshifts by itself to hold back speed, much like downshifting on a ICE car.
I see no need for the paddle shifters.
Wayne
