Hi,
For those inletting English fowler style butt plates, here is how we do it. It is not hard. This is her first butt plate inlet ever. You need to scroll down to almost the bottom on page 7.
https://www.muzzleloadingforum.com/threads/my-apprentice-and-her-english-fowler.155411/page-7https://www.muzzleloadingforum.com/threads/my-apprentice-and-her-english-fowler.155411/page-8
Rasping the face of the butt stock flat is fine when using brass and steel plates that are rigid and strong. However, if I was using something like sterling silver, I would carve the face so the plate has direct support of the wood behind it as much as possible. I cannot inlet these as fast as Mike but I can probably do them in my sleep.
dave