I was thinking the same thing last night. I switched to and overlap mid summer due to a blister it was causing (from interlocking) and stuck with it, I wasn't getting a blister so it was all good. Yesterdays round revealed a case of the shanks, especially half swings, I thought maybe it was in my grip. I tried interlocking, overlaping, weak right hand, strong right hand and wasn't seeing any consistent results with anything. My lessons teacher told me to have a weak (i think) right hand grip, as in I slide my thumb clockwise when I rotate it back. My dad recently had a lesson and his pro said strong. So now, I don't know what to do. A grip should be universal, it shouldn't vary from player to player was my thinking, so what pro was right? I ended it going somewhere inbetween and calling it good.