Trick Flow and Harland Sharp rocker arms Tip to valve stem Geo

I noticed that jessel make a geometry gauge for use with there rockers to tell you how much shim to add under the rocker shafts to place the rocker tip just behind the center of the valve stem on the bottom of the lobe. Wondering what you guys have tried , or did you just add shims till you got what you needed. Jessel has a video also showing how to use there gage.