Just an opinion...
My belief is that the Jerry-Althea-growl starts with the string set up. The higher action allows enough string oscillation to create the growl. If you haven't played a guitar set up like Jerry's, it isn't "high" action. It's about like playing a well set up acoustic. Roughly.
Recently Waldo & I co-conspired on Strat pickguards that moves the pickups toward the bridge. From Waldo's measurements of Rosebud, and his Moriarty we condensed the HHS pattern. I've just finished a Strat re-build with this configuration, and it is...awesome-er. Pics to follow when I have some time.
Then...amp. EL84 will growl modestly through my Mesa > JBL120. 6V6 growl more. 6L6's pushed...GROWL. I don't have access to my home email, but Waldo gave me a great mod for a cap in the pre-amp...that promotes growl.
I don't yet own a Cocobolo HippySandich. But most of the tonal characteristics can be produced with a properly set up Strat with a blocked trem. I'm certain that a guitar with a core of higher density wood will add low harmonics, sustain, and an awesome coolness factor. I can't stop buying amps long enough to buy one. And my son (the luthier) is getting married in July, so my prototype wont come off his bench until Sept/Oct.
That's what I believe on this subject.
Peace
M
"Hi Ho...the Carrion Crow...FoldeRoldeRiddle"