Not using sub-items just sounds like a pointless extension of an already arduous challenge. It's one of the only tools for customization the game gives you, so it'd be silly to take away the only three benefits you can get. That said, it's still quite possible to do without them and only using the default shot - if it could be done with a wide-shot, it could be done without it, too. I don't think anyone actually cares though which sub-item you use.