Sniper, keeping a log is a good idea. I do it all the time. However I like to start when a bow is brand new taking and recording about every detail I can think of. That way when you replace the rigging you set the bow up to what it was when new, not what it was right before the change.

And yes, I log every change I make with the varying results. This is where owning your own chrono helps. Yeh, there is just nothing like tinkering.