Thank you for the uncharacteristically long and fully informative information.
I really appreciate the objective data and experience. I do have a couple of questions.
Please confirm
Typical (aka hunter class) RCBS solid FL die with typical RCBS expender button & deprime pin holder removed?
IMHO this is a good description of process.
https://www.whiddengunworks.com/stan...eloading-dies/
Please confirm, if annealing, neck turning or uniforming performed in post fire-forming case prep?
Please confirm
1- sized in FL die with button expander removed
2- neck expanded with Sinclair mandrel
3- re-sized in FL die with button expander installed?
Please confirm
Typical (aka hunter class) RCBS combination seater & crimp die?
With the seater stem fully retracted, does the case mouth contact the crimp form in the die?
If your seater die is able to correct neck concentricity during seating, I suggest you take very good care of it.
Did you order custom Whidden bushing or non bushing dies?
Is a carbide expander ball or cone available?
Please report results.
Good Luck, YMMV.