Crank, capacity is the final factor in culling brass. But this check is best performed on unsized -straight from the chamber- fully fireformed brass. This, because it's the only time the brass is actually the same size (externally).
Otherwise, (after FL sizing) your not qualifying the brass on it's own virtue. You're mixing in factors like annealing, and case lube consistancy, that can lead to capacity variance which is not a brass issue.
And don't qualify with brass weighing, as this may not correlate to capacity(unless it's leaves the pack in an extreme).
I've had several 'concentricity' gages for comparison, and there are a few things I've learned from that. For one, runout and concentricity are different animals. The Sinclair I linked is actually a runout fixture, and your ammo is not straight until measured so on it. It is not a concentricity gage, and that's fine.
Get your ammo straight first, and it will be concentric as well.
Sinclair's mandrel system is very useful on the bench for more than turning. I use it for necking up while forming wildcat cartridges, and I run every neck over an expander just prior to bullet seating. This pushes any thickness variance outward, allowing straighter seating, and lower TIR off the ogives.
The neck mic is a must for culling brass. If you ever hope to keep straight ammo, you need to cull out thickness variance as measured on the necks(it runs full length of the case). Otherwise, sizing brings out the devil in your brass. Thick areas springback more than thin areas, and you end up with a batch of bananas that only get worse with each sizing. This is not straight ammo(even if made concentric).
The neck turner works fine. Nothing fancy. Just slip a feeler between the mandrel and cutter. Trial & error a few culled brass, till it's perfect. There are different angle cutters available from Sinclair for different shoulder angles(you turn up onto the shoulder a bit). I have never turned brass by hand turning cases. Always used a case lathe. It's enough pain even at that.