Hi Jim! Thank you for the nice comment. Have you ever visited Scot Reader’s t206insider website? Scot is a pioneer of t206 research and his website has a registry that accommodates PSA and SGC entries. It uses some sort of scale that adds points for grade and back difficulty. I really wish more people would use that site. I started adding mine but haven’t updated it lately. His ebook Inside T206 is a must read...I have quite literally read it a dozen times.
https://oldcardboard.com/t/t206/Insi...al-edition.pdf
http://www.t206insider.com/store/c1/insider#home/