Re: Question about the .257 Banshee?
That's right, the 6.5x68s case, hugely improved. It is an oddball case.
If you wanted more info there is a great discussion and JGS reamer print for it in 'Precision Shooting's - Reloading Guide' cr1995.
The STW would be easier in a sense, provided there is no shoulder improving in your plan. The barrel will barely survive fireforming.
This is where Lazzeroni comes in.
Even simpler than wildcatting. Just write a fat check and wait for brown.
I do hope you realize that these are hunting cartridges. They will not handle much bench shooting. Since a good system includes both, I would suggest(just my opinion), that you consider a Savage as your platform.
Either from Lazz, or your own. You can order & switch barrels on these yourself. Hell, the barrels would be cheaper than your ammo!
This way your always up & running.