Re: How much neck tension?
Best regards back atcha. I agree that neck tension is very important, and may indeed be most important.
The problem with bushing dies, etc., is that they are a fixed solution to hitting a moving target. Every time the brass gets worked, it gets hardened, and using the same tools consistently will render equally inconsistent results.
I use my 'find the right adjustment' method each reloading cycle, and while the measurement means may be unscientific, they are somewhat more realistic than choosing a bushing diameter and going with it blindly and unalterably. FYI, as the brass hardens, the resizing dies should move <span style="font-style: italic">up</span> and resize a shorter portion of the neck. This is because the resizer ball encounters more resistance and generates less springback as the brass goes harder.
While many resist employing the resizer ball, they still encounter similar problems due to work hardening. For me, the resizer ball is another subjective means of judging brass hardening.
If the bias on the adjustment is toward the lesser neck tension end, finishing each reloading cycle with a twist can find and cull the ones that are on the 'not enough' end of the neck tension scale.
Greg