This technique seems really good BUT, once again (at least in my own opinion) when your in a game there is only so much time that you have to putt (unless your playing 90 sec shot clock). (and who wants that, lol)
Now if you playing by yourself another story. (but that makes for a lonely game, lol)
One needs to develop your putting by look and feel (especially if your using a 45 sec clock in a game.) sure you take in consideration of the green speed and elevation but judging the slope angle and dot speed, setting up slide ruler can be very time consuming.
Now, before all you pro's jump my throat ,, I'm no expert, my stats can tell you that! lol
1.85 putts per hole, almost 30% one putt, 55% two putt, but eventually getting better. ( that's is based upon my approach % getting better and my distance to hole becoming better.)
So please no harsh comments needed, If you are playing by yourself this approach would probably work well. Great write up and appreciated time put into this.