Along the way, I have come up with a formula that may be of use to other motivated players. I hope some of the golf wizards on this site will contribute to this thread and add further useful insights.
As regards the break, the object of the gauge is to end up with an accurate distance number, according to which the flag will be moved sideways, to the higher side of the hole.
First - and that is the most difficult part of the calculation - we must accurately gauge the amount of break. To achieve that, we must determine the number of parallel lines on the putting grid between us and the hole, and assign a numerical value to the balls that travel along each line, as they indicate the topography, or surface configuration, of the green. To that effect, experience and observation, together with memory, are essential, not to mention the necessary willingness to bother gauging the break accurately in the first place. Weariness and laziness lead to sloppiness, which in turn produces mediocre results, or worse. I know that all too well, as I myself am guilty of such laxity at times. But I have old age and physical disability as an excuse. I'm sure you have your own excuse, defensible in your own eyes. Be that as it may, the result in all cases is the same: don't do the math, be off the path = dismal putting.
Say for example that there are 7 parallel lines between you and the hole, with the following pattern: 1-1-2-2-3-4-3 (the bigger the number, the greater the break).
a) You add these numbers; the total is 16.
b) You take the stated distance between you and the hole: 13 feet, and adjust this number by factoring in the slope. In this example the slope is 6 inches downwards (shown by the color red on the grid, whereas black shows a flat surface and blue an upward one). You add this number of inches to the number of feet, which gives the number 19.
If the slope were upwards, you would subtract the number of inches from the number of feet, instead of adding it to the latter.
c) You multiply 19 (adjusted distance) by 16 (break value). The total is 304.
d) You divide 304 by the number of parallel lines between you and the hole; i.e., 7. The total is 43.43. That amounts to the initial distance number by which you must move the flag sideways, to the higher side of the hole. Note that I attribute the numerical value 30 to the width of each square in the putting grid.
e) In a flat or upward putt, the above calculation and displacement should suffice; that is, the ball should go in the hole or be very close, if you perfectly execute the putt (ding!). But in my example, the downward slope adds a new dimension that must be taken into account. You must determine the fraction that the slope (6 inches) and the stated distance (13 feet) together represent: 1/2.16. You then multiply 43.43 by this fraction (43.43 X 1/2.16 = 43.43/2.16), and add the product of this multiplication (20.11) to 43.43, which gives 63.54. That is the final number by which you must move the flag sideways, to the higher side of the hole. Again note that I attribute the numerical value 30 to the width of each square in the putting grid.
As if things were not complicated enough, there is yet another adjustment that needs to be done for putts whose stated distance between the hole and the ball is 6 or under 6 feet. When the surface is flat or upward, you can reduce the displacement of the flag sideways, relative to the break, by a quarter for 6 or near 6 foot putts, and by half for 5 or less foot putts. When however the surface is downward, you can only reduce the displacement in question marginally, if at all, especially on speedy greens.
Now let us tackle the issue of power. As a rough guideline (each course is somewhat different, Oakmont being the fastest), consider the following:
Adjust the distance when gauging power by factoring in the slope differently than when gauging break. If the surface is flat, no adjustment is necessary, and the stated distance prevails. Otherwise, the number of sloping inches is added to the stated distance (measured in feet) or subtracted from it, depending on whether the slope is upwards or downwards. In my above example, we subtract 6 from 13, and obtain 7 feet as an adjusted distance.
Slow greens: add 1/4 to stated or adjusted distance.
Standard greens: add 1/6 to stated or adjusted distance.
Fast greens: stated or adjusted distance.
Very fast greens: subtract 1/6 from stated or adjusted distance.
Tournament greens: subtract 1/4 from stated or adjusted distance.
Championship greens = tournament greens, only a tad faster.
You should know that very long putts require an additional adjustment, where the end power value (measured in feet) must be reduced by a number of feet. Again, each course is somewhat different, and must be experimented on.
Finally, to those who care to understand my formula, with the purpose of improving their putting, I suggest you peruse the entire thread for additional information or further clarifications.