<HTML>I am in the process of re-regualting a S&S M, where one of the main problems was that the keys were too low, (they were almost touching the front rail when depressed). I raised them all with cardboard and paper punchings. As I was doing this, I got thinking about this question. Are there any rules of thumb, or what is the general consensus, as to what thickness the wool balance rail punching should be? Should we have thick punchings with fewer paper/cardboard punchings, or thin punchings with lots of paper/cardboard? I guess I could ask the same for the front rail. Do we use thick felts and fewer cardboard, or the other way around? Or does it make any difference? Wim </HTML>