What I do while tillering so I get to the weight I want is to check tiller to the max weight. So if I want a 50# bow at 26" I make my long string pull to 50# and check to be sure everything is good them remove more wood, pull to 50# and check tiller, and so on. I get off the long string and to low brace as soon as possible, usually when I get about 8" of tip movement.
If you come in over, remove wood until you get the weight you want. Remember to exercise the wood often as you tiller.
+1
Doing it like this you'll get results that go like this:-
50# at 6" long string (and by long string, we mean only just long enough to get onto the bow)
50# at 10" long string
50# at 16" long string
50# at 20" braced
50# at 22" braced
50# at 24" braced
50# at 26" target weight at target drawlength.
If you keep pulling 50# you end up at 50#!
The main adjustments of tiller are in the first 4 readings, after that it's very fine tuning and removing wood v carefully to ease it back.
If you are not heartilly sick of putting it up and down on the tiller and exercising it, then you aren't doing it enough!
The hard thing is getting your eye in to seeing problems before they are too obvious... also knowing how much wood to remove to achieve the desired result.
The whole process is one of successive approximation and prevention rather than cure.
When in doubt, stop, take pictures and video, look at how the bow actually flexes, not just the static curves.
Del