A lot of guys use a "honed" sizing die in this instance.
A honed die, doesn't size the neck down near as much saving it from working the brass a bunch.
That way your mandrel will only have to expand or work the brass athousandth or two to set final tension
Lots of past discussion on honed dies here on the hide.
I'm not an expert, so I will have to defer to past threads.
Search mandrels or honed die if some of the heavy hitters here on the board dont weight in here.
This comes up pretty regularly. Lots of discussions in this. You can leave your stem in your sizing die if your decapping....just remove the sizing button from the stem. If you arent decapping then just remove the stem all together....