As Rob says above, a new revised version of Ampersand's Modeler's Guide to the Sherman is supposed to be in the works. It will supposedly contain the turret info that was missing from the first version. Lots of us waiting for that one -- especially the yo-yos like me who procrastinated on getting the first edition and ended up being left in the cold.
Luckily, I've had Hunnicutt's Sherman bible since the 80s. A friend had it and I was always borrowing it. One day I went over to his house and noticed another copy sitting on his bookshelf. He told me to keep the one he had "loaned" me -- Happy birthday, Christmas, New Year and Father's Day. Not many friends like that!
After all the crazy prices that are being paid on eBay for the Hunnicut book, I've let the spouse know that if anything ever happens to me, she better make sure she gets fair market value to my dog-eared tome, and not drop it in the Goodwill bin or sell it at a yard sale for a quarter.