A rule of thumb is to always size brass fired in YOUR CHAMBER, the minimum amount need to allow the sized brass to again chamber in YOUR CHAMBER!
If you will send me a "PM" with your personal "E" address, I'll send you a document which addresses the situations you are speaking of.
Same offer for anyone.
What your are looking at here is the issue of manufacturing tolerences, and how to properly set up your dies to minimise the problem.
I don't know about Dillion, but although RCBS makes very good equipment, their set instructions fall way short of reality. Hornady, also a good equipment manufacture, includes a "foot note" which helps to adjust for the problem.
However, even Hornady does not go far enough in addressing the situation and how to correct for it.
Crusty Deary Ol'Coot