Fubar057: ,my main question is how much harder do u hit a putt when the line goes from dark blue to light blue.????
My short answer: no differently than if it was uniform blue all the way to cup. The general rule of thumb is add 1 ft for every inch up or subtract 1 ft for every inch down. Figure the basic distance first, depending on green-speed, THEN correct for elevation.
The reality is the lighter blue at end of roll means you're putting up to a tier. You really have a 2-part putt - the first part up the hill, then a more level or even maybe a tad downhill finish to the cup. I like to take a little bit off in that situation - say a foot or 2.
That rule of thumb breaks down at large elevation changes btw! My experience is a good correction for large elevation changes is 10 ft/foot of elevation increase. I.e., 30 ft standard speed putt, up 3 ft, I give it a 60 ft whack.