So, i appreciate that this is an old post, but seeing as i was looking for the same info and as near as i can tell does not exist on the internet, i decided to update this post.
I am shooting 450 in a Ruger American and AM seeing the brass grow by small amounts each sizing operation. What i have found is that L E Wilson case holder for a 45-70 (fired case) fits almost perfectly. I say almost because the head of the case is within the case holder, but the tailpiece of my trimmer is smaller than the case, so all works.
Hopefully this helps the next guy