Over the last couple days I've figured out where I want the throttle pedal. I'm using a toyota prius hall effect sensor pedal. So this pedal takes 5v from a power supply and then sends out a 0-5 volt signal to the controller depending on position. I'm going to set up a "hot pedal" regen brake system. This means the regenerative braking will kick in as soon as I start taking my foot off the "gas" pedal and even before I hit the brakes. I've heard that the Tesla model S has this setup and people like it a lot. I've heard people say that it is worse for your efficiency because you don't coast. Maybe, but the amount of energy used to spin the motor at the same speed as the drive wheels is probably only around 200 watts or less, which (although not a good thing) is pretty small compared with the 16,000 watt hour battery pack. I will monitor the motor as I start testing the car and if it seems that the free-spin draw is excessively high, I will switch over to the standard regenerative braking activated by the brake pedal. This will allow me to coast without any draw on the battery pack.

To set up the throttle pedal, first I made an aluminum mount in the approximate shape that I would need. I cut it across the front so I could bend it at the bend in the firewall of the car. I bolted the aluminum where I wanted the pedal. Then I duct taped the pedal to the aluminum mount and tested using it. It turned out that it was too close to the brake pedal and I kept bumping it when "emergency" stepping on the brake.

Next I modified the aluminum mount so that I could move the pedal over to the right slightly. I TIG welded the aluminum at the angle that I wanted it and bolted the pedal to it.

In this final position I was no longer bumping the throttle while hitting the brake and the throttle was comfortable on my foot at all angles.

Voila! I still have to hook up the wiring and run it to the controller, but the mount is solid and I like how it feels.