Watch the Larry's Trick Solo 2 online guitar lesson by Chris Buono from Guitar Lab: Blues Soloing
When the second and third choruses roll around take notice of how the b7 of the G7 chord, F, is never played over the 6-9 slide chords. It clashes with the chord tones within those two chords making for a clam waiting to happen. This, as with many instances to come, will guide you down the path of more "responsible" soloing. Meaning, if you want to play over hipper changes, you can't always just blow over the chords with a horizontal minor pentatonic approach and hope for the best.