i took a porch swing I bolt, some fairly big washer and 3 nuts 1 lock washer and extended my gas pedal all the way over to the right. I also layed a flat piece of medal on top of this and wrapped it all in black electrical tape and it sure worked for me. I had the same problem, and with my big clod hoppers i had to do something.Mine feels rough at slow speeds. But I think it is due to the gas pedal being in a wierd spot. When I hit bumps at low speed, my foot cannot stay stable enough to keep the pedal pressed the same, so it makes the machine lurch.
When I go across rough terain, I just keep it to the floor and it rides as smooth as butter. I will see if this changes once my pedal extension comes in. At least then, I should be able to rest my foot agains the hump to maybe stabilize a little better.