FitzTheRuke
Legend
I'll treat it like I treat new games, new editions, and new recipes. Follow along as written at least once, then fiddle with it.
That said, the autosuccess on a nat 20 is going to be a pain to deal with. The current player habit is to shout out a skill name and chuck a d20 before waiting for the referee to even acknowledge the player's said something, much less sussed out the actual interaction of the situation. A player who's yelled a skill name, thrown a die across the table, and sees a nat 20 is going to be even harder to talk down when the rules specifically tell them they've autosucceeded at whatever random thing they think they're doing without consulting the referee first.
Not much you can do with the rules to avoid inconsiderate players. The best thing to do there is to tell them that they have to "play nice with others" (and that this behavior doesn't qualify). Heck, maybe being told that their unasked-for crit does not, in fact, count for anything, will help to teach them to wait before they roll, because there's actual consequences for them for their bad behavior.