Large is to big. If his heel was all the way back in the cup there would be no overhang at the toes and he could move the binding closer to his toe edge. The gas pedal also needs to be on the smallest setting and even then may be to far forward to provide any leverage. Toe straps also look about maxed out on the smallest setting
Do you have have a friend that knows gear that can help you with your bindings? If it's not to late I'd exchange them for a medium. If you've already used them I would talk to the shop and see if they are willing to work with you especiaaly if their employee put you in a large binding.