I think flashhole is saying to use the runout tool on the case necks first and concentrate on those that are the most concentric. Outside neck turning will lessen the neck diameter some, and bullet tension as well, that could be of some consideration. If I were undertaking your project, before neck turning or inside reaming, by using the competition die sets I would first see how little runout can be achieved by that alone (as well as checking case necks for minimal runout to start with). If you can then achieve a majority of rounds with .003 runout or better, that may suffice without case neck turning. The only time I tried something similar to this was with mostly standard dies and used with sporter Mdl 70 and 700 rifles of various calibers, but accuracy improvements, even with .003 or better runout, were not particularly good. But possibly so with a tuned rifle. I did acquire some inside neck reamers but quickly gave up on that due to case neck thinning.
