You should get off the Internet, pick up your calipers, and start giving yourself real numbers to work with.
Run casings in various ways, MEASURE said casings, and record what the die produced when you followed "X" procedure. A realization will be that what the die and/or bushing is stamped is not usually what you get.
You're looking for something that gives you a casing that fits the chamber (it's a-okay to use the ACTUAL chamber to check this), is round and all parts are round at the same center as all others, and whose neck diameter is about 0.002" LESS without a bullet than it is WITH one.
But tools and time are the only way to answer your questions with certainty. You will become educated, rather than taught.