I recommend you watch this Interview between John Feigenbaum, CEO of Whitman Brands and Cabbage Coins, specifically about running and modernizing the Greysheet, how they value coins. Good history lesson on how that publication has evolved, also some insight into how they ignore outlier comps from well-heeled (need to have it, at any cost) collectors, how collectors should use the Greysheet pricing guide, and other topics of interest such as stamp collecting and the Redbook. My only exposure to the Greysheet is the pricing info accessible for registered users of CAC, I have never used the printed version. I still found this interview very insightful into the coin hobby, check it out.
No surprises for me really but I think it does an excellent job of explaining what the Grey Sheet is today.