I've been focusing on improving my ball striking lately, specifically ground strike, face strike and face direction. One of the ways I receive feedback regarding face strike is to make a little dot with a dry erase marker on the ball, position the ball with the dot facing straight back, then hit the ball and then look at where the dot imprinted on the face of my club.
My question is: Is there any reason I can't do this during an actual round of golf? I play in a league that's pretty serious about rules, and I want to make sure I'm not doing anything I'm not supposed to.
Most of the people I normally play with wouldn't care anyway, but I'm just curious where the legalities on using things like that to receive feedback during a round.