Are these custom guts you have made? I have not heard of shaping the guts before.
Yes, they are a custom gut.
Doug showed us how to set up a jig in KC this year. It is very simple and helps sand the angle on your toneboard.
I took what Doug showed us. played around with it and ended up with a set of guts that I like. After that I used corion to make a nicer jig that made it easier to replicate my guts.