I was a club fitter at Dicks Sporting Goods for a little over a year before returning to coaching. This is one of the ways I used to fit customers for lie angle. Ball flight is the second best. I used a wider chisel tip sharpie. Sometimes I would also use a line drawing aide that you put the ball into to ensure that the line was straight. Lie boards are unreliable for the simple fact that the club head will skip or skid and straighten out at impact. On grass is definitely better. You also have to remember that golf clubs are longer now than they were 20 years ago, primarily to "prevent" slicing ( I believe the theory was that since most people slice, if a club is slightly longer, thus more upright, the heel contacts first and "closes" the club face).
