you are getting the idea :)
I highly suggest putting tips tuturiol to all by NIVIAC; found under FAQs in forum....EXCELLENT piece!!! Each putter has its ranges assigned to the club. Pick the range you are working with; then count the each pullback movement until you reach the end. Now, divide the number of pullback movements into the range....so yes, 5 pullbacks on 50ft would be 10ft for each movement.
Your description for 2 pullbacks on 25ftwhich is 10ft per pull, pls 5 after the 2nd pullback. You are looking at either 2 & 1/2 divided into 25ft = 10 OR it is acutally 3 pulbacks which would = 8.3ft, call it 8ft per pullback. you'll have to experiment by putting into a open area of your practice green. I had a similar thing with my Rosewood putter.
Originally, i thought i counted 2 & 1/2 for 15ft which = 6. Then I went to 30ft and counted 6 which = 6. Then I went to 45ft and counted 5 which =9.....90/7.5 = 12..150/10 = 15...300/10 =30. When I was looking at the numbers I realized that the 2 & 1/2 for 15ft had to be wrong because you wouldn't have two ingriments of 6 when all the others were spread out by ingriments of 3...6ft - 9ft - 12ft - 15ft - 30ft....so i decided 3 pullbacks for the 15ft which = 5; giving me a spread out range of 5-6-9-12-15-30.
Of course you have to adjust those ranges to the green speed you are playing. Hope this helps.....And again suggest Putting Tips by Niviac for all players; it will help twik you putting game; it did for me.. :)