Yes, I am a guitarist and I was aiming for those keys, although B is uncommon. I chose it for this tune when I played it on guitar, because the IV chord, E allows that nice bass line after the breaks on the I. This actually is a vocal, but I didn't want to send it to my sax teacher in that form.Nice. Down and dirty, as they say. Once again, it's easy to hear you're an experienced musician but it's still impressive the tone and technique you've got in 2.3% of your lifetime.
What key? No idea. I think some people have said guitarists have favorite blues keys, so if you're going that way...ask the guitarists? Otherwise, maybe work thru all, around the Circle of 5ths? Or is it 4ths?
You're right Rhys! I would also like to hear more "ad lib "blues songs. I don't mind if the song is in the original key, jazz blues, blues rock, country blues ...... From Ellington, Lester Young, Gene Ammons .... to Stevie Ray Vaughn, Chuck Berry, Eddie Shaw ..... I'm going to record some more blues songs. I do it my way. That's mean more as I was playing at a blues jam.