I have never measured it in .001's. I do use the Lyman M-Die. I belive that die does a better job in flaring the case to accept the bullet. And I do adjust that die to each load(which means you have to trim your cases or readjust with every firing). Especially if shooting a hot load and you have some case expansion.
I flare the case just enough so that the bullet will start into the case about 1/16" without shaving the side. That is the farthest I like to flare the case. And you really can't measure that in .001's because every die, every brand of brass, and every bullet are going to be sized differently. So a fixed size would not work for different components.
This is another reason why I always load my revolver cartridges in bulk. Tom.