I've always played my practice rounds for a tournament in a different fashion. Not really worry about the swing or the putting stroke, more interested in collecting correct data and getting it so my eye 'fits' the hole. There have been almost countless times where I would hit about a dozen balls off the tee just to find the right spot on the tee and the right target so the hole fits my eye. Then in order to not hold everybody up, I would just pick up all of the balls and go to the next hole. Lots of work on yardages, etc.
But, back when I was playing tourneys, we didn't have rangefinders and Breakmasters.
Anyway, one thing you will find is that the majority of greens slope in the same fashion. And if not, then the majority of the rest of them can be 'split' into two or three slopes. For instance, the first hole at one course I play all pretty much breaks towards the bunker. I found a house out in the distance that is pretty much where everything breaks. Then the second hole can be split into two. The left side will break back towards the #2 tee. The right side will break towards the #8 green which are in different directions.
The pro caddies are much more elaborate. But, if you've got a home course and you can get a pretty quiet round by yourself, you can do it rather easily and just make some quick notes. Even if you're always playing with friends, bring it out for a few holes here and there as I found that most people think it's the coolest thing ever and like having it around.
3JACK