We've had our MH two years this year. My problem is my feet aren't that big - size 8.5. When driving to get the best leverage on the accelerator my foot is halfway up or at the top of the pedal. This ...
The OP has indicated his problem is that in order to depress and hold the pedal while driving, his foot has to be completely off the floor. This is awkward, uncomfortable, and tiring.
I'm not sure how a pedal extender will improve this. While the extender brings the pedal closer to the driver, it moves the pedal further away from the floor - meaning the OP will still have to hold his foot completely off the floor in order to depress and hold the pedal.