I don't think anybody is saying larger is better.
But you are saying that. Lets not walk away from that.
The original factory dimensions are to provide clearance of the case during extraction. There are a lot of factors that work into that, brass hardness changes as the brass is work hardened. If that diagram I posted is to be trusted the harder the brass, the more of an interference fit you get.
What we are saying is why waste money on a small base die if the normal die works fine.
I don't have the means to measure taper, and I will bet you don't either. You are probably just shooting and it goes bang, fine. I paid Compass Lake to cut me reamer cut cartridge headspace gages. These are gages cut with the exact same reamer that is used in cutting my rifle chamber. After sizing with standard based dies I found the occasional "sticky" case. Not much, just took light finger pressure to seat, but there it was. An interference fit.
People get away with these light interference fits as the bolt crush fits cases to the chamber. They are also getting away with it during extraction as the extractor is able to drag most cases out of the chamber.
The occasional malfunction is just chalked up to “bad luck”.
I just read in Rifle magazine that manufacturer's are using larger chamber reamers. This is an endless cycle to the bottom, neck sizing, partial neck sizing, standard dies cause malfunctions, shooters complain, it is never their fault, so the manufacturers' make larger chamber reamers.
We know that standard base dies leave cases larger, and I have not heard of a good reason why larger is better.
So why is larger better?