For me, Betts is relatively easy to copy. Not easy like, it doesn't take work and repetition to learn, but it's do-able, mostly major, Dorian, and blues scales. Garcia seems to just throw in random notes and make it sound cool. I wonder, did he think, "How 'bout if I throw in a couple Phrygian notes leading up to the relative minor, then echo that theme leading back to the one chord"? Waaay over my head. Ranger, I think you are correct; he got a lot from Django.