I have never seen him in concert but he was a big influence on my playing in the 1970's. The first album he made with Rory (Aurora) Block and the tablature book that it came with got me started on finger-picking and I haven't stopped since.
The first piece I leaned was Gary Davis' 'Delia' and then Dallas Rag (see below) was the first sophisticated piece I learned soon after.
Right now I am transcribing the music of Blind Boy Fuller and Big Bill Broonzy as a current project for a bit of musical fun. My ability to take that on is in large part thanks to SG's teaching efforts while the rest was down to a good friend who let me sit and watch (memorise and steal) his finger-picking rags and blues.
Have you seen this? SG from his younger days playing Dallas Rag.
https://www.youtube.com/watch?v=SMICKJQMldA