is it allowed to be "close enough"?
you know, you don't fit all the wee intricate links into the verse riffs etc., but you're playing the right chords etc., so it'd be good enough to wing it (if it weren't being recorded, for example)....
assuming "close enough", i guess somewhere between 5-10, at poison/ac/dc level of difficulty (no jazz chords, minor pentatonic solos, etc.)