I made a quick video demonstrating the installation procedure for the Grip Loc interchangable thumb system using the KMT Personal Ball Jig.  It is a very easy system to use and it should eliminate the need for different size drill bits for different size thumbs.  All you need is the 1-3/8" bit.  Then you just select the correct size inner sleeve, round or oval! http://www.youtube.com/watch?v=zyf-Y7iGkLU