My first thought was to say "don't buy it" but too late..
Here is my advice to you...
Give the putter pal a try. At worst, buy the 10 hits and then make you own template, continue to use the putter pal or..
With using the putter pal, with each meter scale, drag back the meter as you would by using the avatar movement method, and write down what % each movement stops at.
From there just do the math. If the first movement of the 25ft scale goes to the 30% mark, then just take 30% of 25 and thats the first movement length.