Watch the Ford-ward Solo 2 online guitar lesson by Chris Buono from Guitar Lab: Blues Soloing
You may find the changes a little perplexing at first. The initial quandary may be deciding what key this jam is in - G# minor or B major? While it could go either way my ear votes for B major. Just listen to the resolving quality the B7 has when it's dropped in bar 3. But, at the same time, I wouldn't be surprised if someone hears it as G# minor as that does deliver the goods when coming back around to the top. In the end, let YOUR ear be the guide and play accordingly. As stated: As long as your phrasing is there, so will you be.