I found training on my touring bike to be real easy for one-legging. It has a rack, so I unclip the one leg and put the foot back on the rack so its not in the way. Sounds awkward but its a stretch and excersize at the same time
I like to vary the foot angle periodically. Sometimes droop the heels below the pedal, sometimes pedal "ballet" style with heels up. But level is the ideal to start with. The most effective stroke I have found has a degree of heel movement at the ends, it reduces some of the knee stress as it goes.