I do that also. It would be easier if all clubs were the same scale size so it worked for other clubs not just the putter. My driver and iron scale is almost 1/4" longer. It sucks. So when the Putter Pal was applied I was able to use it and make a tape for my other clubs. It worked out great. Then one day my putter pal disappeared during a game and caused all sorts of problems. I have no way to put it back up as I do not have a putter pal option.
As for a post it note. That will not work for me. You must have a small screen. My scale is 5" long.