I don't see it on this site. Search Eric Krewson in Youtube and it should come up. It came up second for me.
The gizmo is really awesome at this stage of tillering. Even if you aren't going for a circular tiller it would pick up those areas wizardgoat pointed out. And after you use it for a few bows your eyes will start to get trained to see those spots on your own.
I've made a few bamboo/yellowheart bows, maybe 5. It can make a nice bow but it will fret if you push it too hard. I'm a little concerned about the length of this bow even though you are only drawing 26". Even more reason to perfect the tiller before going any further.