I started using a gizmo a couple of years ago. Great tool. I make mine 4" long. I might try 6" and see if I like it better. I like a bit more of an elyptical tiller instead of circular so I have to play with it a bit. I start off getting it bending equal then use it to increase the bending radius mid limb by comparing the two limb marks. I was trying to figure out a way I could modify it to change the width of the mark as the depth changed but didn't come up with anything uncomplicated. It would be possible to make an air brush type set up where the pencil was replaced with a needle in the tip of an air brush that changed the spray pattern as the needle changed depths. But a little too complicated.
