Hi Tom,
Isaac was a great guy, a remarkable talent, and a very good teacher, but, whilst I might be wrong in this, I don't think he was ever the type of musician /teacher who thought in terms of learning note for note as tablature implies.
I played on the same bill as Isaac a couple of times and saw him whenever he came to my area.
Once as a Folk festival he gave a workshop early on a Sunday morning when, I confess, I was not at my best, (you can imagine)
These two videos, courtesy of Bristol Ron, show his teaching style.
and
I'd suggest that his concept was a) understanding how music"worked" and then learning the chords of the piece you want to perform, and then simply working out your own arrangement.
There usee to be a website where he gave this info more slowly and in an organised way but seemingly it no longer exists.
There is an insight into his style on this website:
http://www.anetstation.com/guillory/ - and go to "school"
Of course the other thing to do is to get hold of as many of his albums as you can and "absorb" and adapt his approach.
This may still be a source of his albums :
http://intuitive.productions/web-store/
All the best, Ol' Andy