This will be interesting to watch. From my experience, I think alot of the "which die/process works" will be determined by the difference in the neck OD of the sized case versus the sized case. Just makes sense to me that the more you have to move the brass, the more opportunity for "error" introduced by any process. That's why the first thing I do before buying dies is measure a factory round neck OD and then measure a fired case from the rifle. I select dies based on how much I need to compress the brass. Also, brass quality would need to be consistent across the calibers so you don't get any quality x process interaction.....I guess what I'm saying is if you want to test just the sizing method, you'll need to control as much non-die-related variability as you can or you won't get credible results - the results will be commingled with whatever factor you didn't control...That being said, I applaud you for doing the test.

Two things I hope you'll keep track of and report:
1. for each caliber - difference between fired case neck OD and sized neck (as per above)
2. Mark/number your cases so that you can discard one or two if the continuously show poor concentricity (i.e. high variation in neck wall thickness.

Elkbane