cyrusthegreat: Say the lower two levels on my putter are 10 feet and 20 feet. Is there any difference at all between swinging with 100% power on the 10 foot scale and 50% power on the 20 foot scale?
No difference. However, you may find that you are able to hit the ding easier if you use the higher scale (eg. 20 ft scale), because the meter will not have to travel as far.
I have a putter with 10-20-50 foot scales. I use the 50 foot scale for almost all putts over 7 feet. I only use the 20 foot scale for putts where I want to hit under 5 feet of power (eg. 25% or less), or when I have a touch putt (i.e. a very short putt with a lot of break) where I need extra precision on how hard I hit it. I only use the 10 foot scale for tap-ins.