It is my experience that as long as you hit a wood or iron at a minimum of 70- 80% of the meter length you will get a corresponding distance from the club. For instance if you hit a 200 yd club at 90% of the meter length, the ball will travel 180 yds assuming no wind and no up or downhill. I attempt to avoid hitting any club , other than the putter, less than 70% as results don't seem to correlate as well between the meter %tage and the distance traveled.
BTW, the putter works the same way with the caveat that I have no trouble using the entire length of the meter to to find the the distance needed...for instance, if I have a six foot putt with the 30ft putter I would calculate that I need to bring the meter up to 20% of its length and release...I usually give it an extra click or two up the meter to ensure I am not short with any putt...hope this helps....HBthree