I just got a string of emails from a bandmate with the changes to 12-bar blues tunes as played by Clapton. It's not very nice of me, but I play whatever substitutions work at the moment, and they work. It's 12-bar blues, for cryin' out loud!
They fired me a while back because they found a bass holder who *sang* (I haven't been). Ironically, I play more with them now than I ever did before they fired me, and occasionally I remind them of that (their reactions are mildly entertaining).
I do the gigs because I absolutely love playing with the drummer and the keyboard player is someone I've barely known for years but only recently have become good friends with. The three of us always have an excellent musical adventure, because we pretty much just take over whatever tune it is we're playing. I have made it abundantly clear that I will only play when my drummer-of-choice is on the gig, because life is too short to gig with bad drummers. The bandleader is malleable enough to accept what we do as art, even if it's not like the record.
I have to say, though, that the bandleader (guitarist and vocals) and the singer are terribly nice people, just very new to this business of playing music.
John