Thanks for mentioning these alternatives. During travels I use the official putter pal - maybe I should have a look at your proposals.
Usually, I prefer to have no extra load during the games, and there might be the unjustified allegation of cheating if it shows on screen shots.
Paper pal has been fixed to my screen for a long time now. WGT's variation don't bother me since I position and resize the game window when necessary so that it fits to the fixed meter.