The three necks I purchased fitted really well to Fender size bodies. A Guitarbuild.co.uk P body, a Squier CV Jazz body and the Squier Tele Ray body. I had no issues with tuner hole size. I used Fender MIM tuners, Squier tuners and Fender US tuners. Maybe I was luck I'm not sure but quality of the necks is pretty good, but the '51 P headstock shape  can vary.