what you do is also dictated by green terrain, course and even wind (yes, wind does impact distance for longer putts).
Plain downhillers, use the known reductions for green speed (slow = +10%, STD = 0, Fast = -10%, VF = -20%, Tourney = -30%), then deduct a foot for each inch of drop. Finally, add 1-2 ft 'safety factor) to make sure it gets to hole.
If you have a strong tail wind (>10mph or so) and a longer putt, drop the 1-2 ft safety factor.
If it's a big breaking putt, you'll need to add a bit more for the long path of the roll.
Oakmont and Olympic downhill putts want to run; I drop the safety factor or reduce it - depending on wind.
If you're putting from an upper tier to a lower one, consider breaking the putt into 2 parts (reverse the procedure if you're putting uphill to a higher tier):
- Part A is getting the ball to the edge of tier you're on; calculate distance (as above) to point where you want the ball to reach the upper edge of tier (including safety factor). this part of the putt may even need uphill correction.
- Part B is the remaining distance, corrected for green speed and remaining elevation drop, with NO ADDITIONAL SAFETY FACTOR.
Longer putts that go up and over a high point, or through a dip, I treat like a plain putt.