This is a bit beyond my ken, but since I have one Warlocks post, and an early Phil post, and since LLD has a Menlo Park angle, I thought I'd make a note of it. This may well be in the record, but I don't recall it. This is from a ca. early 1991 interview with John Dawson.
Describing his hook-up with the GD and eventual NRPS people, Dawson notes that Garcia and Nelson gave music lessons "at various and sundry music stores around Palo Alto." He mentions Dana Morgan's of course, but also describes Dana Morgan, Jr. leaving and Phil coming in thusly: "It was in a different music store called Guitars Unlimited, which is in Menlo Park."
Again, I haven't consulted my old GD stuff in a long time, so this could well be well-known. I thought I'd put it out there for you Menlo Park types, just in case.
BTW, Dawson also mentions a place called Pinky's Pizza in Menlo Park as the place where Dana Morgan played with the Warlocks. I have no idea if that's new information or a muddle of Magoo's, but, again, there you have it.
Source: Brown, Toni A. 1991. New Riders of the Purple Sage Interview. Relix 18, 3 (June): 19-20.