I enjoyed that progression. i think I am with u this time around. If u use the b natural it would be after u established the key. The b natural to a b flat could be used as a grace note... an embellishment of sorts. A raise 1st or 8th. Wow that's a new one on me!
Right, a grace note, although A natural makes up a more traditional grace note in Bb blues.
You can also try a B natural one-bar-long note on a Bb blues first measure, it may sound weird at first, but in jazz it just means you are playing in a decidedly outside, untamed style. Both are good, tame and untamed ways of playing, Mulgrew Miller could play either exceedingly well.
