You could still get a hands free ability once you set the speed with a lever attached to the foot pedals if you add some sort of friction disk to the setup that would hold the position of the lever against the return springs on the pedals, or you could create a channel for the lever to slide in with notches on the side, and then you could move the lever to the desired position and then slide it sideways into one of the notches to hold the position against the return springs to free up that hand.