Welcome to the grumble Ice!
I think I know what your asking... I'll just tell you how to do the whole thing so I don't leave out anything so take what you need & leave what you don't. Anyway, It's probably much harder to use the filletmaster. I would cut the inner frame on your chopper/saw at the size you need the frame to be. Then when it is all glued together measure the outside of the frame and then cut the second frame to that size. When both frames are finished put the inner frame inside of the outer frame. If the back of the inner frame comes up higher than the outer use offsets and if it is lower than it use framers points.
Good luck!
Angie