Watch the Up a Flat 3rd: Alt. Dom. II-V-I online guitar lesson by Kenny Wessel from Shades of Jazz
Lets improvise over this II-V-I progression: C-7 / F7alt / Bbmaj7. We'll take turns blowing over this 4-bar progression, each taking two times through the chords.
C blues scale (minor pentatonic) to Ab blues scale to an A blues scale. Next we'll use these three modes, all connected chromatically: G blues to Ab blues to A blues scale. Lets go!