Rob was kind enough to send me a copy of his pattern.  I have since made a few.  I find that for best use, you have to make sure the thickness of the top of the T should be kept to a minimum, else it interferes with string groove in use.  Overall - - excellent design and simplicity itself.  I plan to give one with each new bow so I never heave to hear excuses for not using one.     Thanks again Rob!!!!