Jon - I don't mean to be a pest but if I understand all of the above, you agree that the 600 (since I already have it) is a good step to take. It may not be spot on for calibration but there should be a noticable improvement and from there I could pick up a calibration kit to experiment. It seems to run so well I hate to mess with it but if there are significant improvements to be had, I'm all for it! Thanks for you help.
Ron
