I always test out both clamp tightness with the string i am using by adding 10 lbs to my reference tension.. making sure the setting on clamp is just tight, no slippage and not damaging the string before hand. Use the part of the string close to the end for the test so that that is no over stretching / dent on the string that will be string onto your racquet.
Oh, btw... a lot of people migh have slippage issue when their fixed clamp's gap is non of equal distance. This can be adjusted with the 2 small allen scew on most fixed clamp.
Last edited by kopfan; 11-16-2012 at 12:47 PM.