Some time back, I did a project that involved using a ream die, with the reamer guided by the die and the case fully supported, and then outside turning the necks to final thickness. The necks were not as concentric before turning as after. For that application, since it was not for a shortened case, there was no advantage, but for yours there may be. It sounds like Jim has the right combination.
Boyd, this may not have fit you application, but when I form cases and use a piloted inside neck reamer (or bore the necks), I think it important to first take a very light cleanup cut on the outside, then fireform, before making the inside cut. TJ Jackson gave the needed sequence of steps way back in the 1990s.
Fireforming does not "iron out" small irregularities, but it does do a good job of general forming, as long as you keep the pressure around 50,000psi.
In point of fact, since I was pushing the shoulder way back, I would make the basic case, fireform without a bullet, now lightly turn the outside neck so the cutter went just a bit into the new neck shoulder junction, fireform without a bullet again, then use the die. The die was made using the FL die reamer, so the case was fully supported.
Not only were the case walls very even, but a large percentage of the cases showed so little runout the needle on a .001 dial indicator barely flickered.
This is a lot of work, everyone has to decide for themselves whether or not it is worth it. I'd note that given decent equipment, success at short-range BR is mainly about learning to read the conditions (wind and mirage). Success at 1,000 yards is all about making as good ammunition as you can. The 1.3 to 1.5 second bullet travel time allows all sorts of things to come into play that just aren't significant and 100 or 200 yards. How many short-range shooters even think about the Standard Deviation for ballistic coefficient (drag)? No reason they should. At long range, it can be worth 3-4 inches. Etc.