Hi, in my amature opinion you are doing it right. I also pull about 50 times an inch but I do not leave it pulled on the tillering tree any longer than needed. Particurally when I get over 17 inches or so I try to avoid leaving it drawn for an extended period. Sometimes I run back and take a picture and then look at it on the PC. Once it's close to done and the tiller looks good I leave it braced (just by the string) for an hour to "settle in". Not sure if that's doing it right but it seems to be working. Best of luck!