Well I just got off the Lee site - resizing seems easy enough. Now at least I know what I need to get should these bullets work.
What I may do is get a .454" die and a .451" and bring down the .458" bullets down gradually rather than trying to go from .458 to .452 then .451"
One other question to you Semi - Did you try shooting the .452" bullets? It may be the additional .001" may be just a tiny bit tighter and may engage the rifling better. They will possibly be a little bit harder to start but once the rifling is cut, they should go down pretty easily.