<HTML>I set the amount of overpull depending on how flat the piano is.I use a FAC tuning from A0 up,tuning unisons as I go.When I get to the treble, the flatter the notes are,I compensate by spinning the lights sharp by an amount,relevent (not equal),to the amount they are spinning flat.Or you can just recalibrate the machine as you go.If you relax the string to the low side,string breakage should not be an issue. If the strings are very rusty, I will lightly dab them at the termination points, with Liquid Wrench.On a string in average or above average shape,I think I've read you can overpull it 100 cents, which I don't try.Also I think in the Reblitz book(maybe another source),as well as others,I've read the pitch-raise is immediate,not something that sinks in later,although instability is an issue.I usually tell the customer ,sources recommend tuning the piano again in 3 to 4 months,although I suggest tying to get six months out of the tuning.The guy I apprenticed under said pitch-raising was like putting up a clothesline,It looks great until the clothes are hung out,and then it drags the ground in the middle .Most people can relate ,the string stretching with this. My 2 cents Hazen Bannister P.S.- come to Carolina and I will love to demonstrate.</HTML>