A proper die that seems to do a better job, indicates off the front drive band and then end of case.
Sometimes you need to rotate case 90deg. Because of some variance in rim flatness but the front of the rim and radius into case body gives a lot of dimensional variance , more than side to side with some rims.
Some smiths have found this important under “ some “ circumstances in some barrels, usually heavily MI ones.
Also certain types of chambers. For instance if you have an MI barrel and it has a chamber cut for fairly full engraving with a short lot......it may hate long lots, some of which may be .010” longer. If you recall, this is why, I would bet, the WLM used to post often about ELEY publishing OAL data on lots
I have measured a fair amount with the die my gunsmith made but he has typically cut a mid depth chamber so my barrels seem not to be OAL super sensitive although I’ve seen that it will change the way fouling in the throat develops