So this could tell you the maximum the pencil should stick out. You could set it like that to start and then scrape away the pencil marks. When the Gizmo stopped marking you are at the max bend?
excactly
EDIT I am trying to under stand an order of operations for tillering with the gizmo
so you would input...
1. the gizmo base length
2. a "not to exceed" working strain
2. the thickness of limb in the area you are tillering
output would give....
a pencil stickout length to use on your gizmo that would not let you tiller beyond the chosen strain?