Be glad that is a supply. Returns must be at least 10 ft away from the stove. If it was a return it would have to be capped off or the stove relocated. I would not notch the shield. If the supply grille is shallow, the warm air from the supply will not be significantly blocked.Yeah that was straight from the guy at jotul North America. Adding a metal plate 1” off the wall seems like a very cheap form of safety. Btw, what do you think about me making a 5x10 notch in the bottom of the wall heat shield for the furnace heat register (not a return unfortunately)?