I've always thought of covers as interpretations of other people's songs. I don't try to replicate what somebody else has done and don't listen to songs much before we try them out. I play what I think fits and then have a proper listen to the original. Guitarist does the same and we sometimes prefer what we have come up with. Some bits have t be spot on of course. I once played in a band where the guitarist (who was a complete control freak) once said to me "The bass part doesn't go like that" to which I replied " It f***ing does when I'm playing it". I think tribute bands need to be as close as possible to the original, but covers? Would be bored stupid trying to get everything note for note.