hi I recently purchased a David Gilmour autograph on a music sheet from “the wall.” It came with a letter of provinance but I think it would add value to have it authenticated. With that said it was suggested to me that I get it authenticated by JSA because they deal more with music. I want to add the best value I can for resale. Should I use PSA or JSA or what do you suggest? Who has the most credibility regarding resale valueI guess is what I’m asking. Thank you so much in advance for your…See More