"How's the availability of brass for the .35 Winchester now?"

Bertram is the only headstamped source. However it can be made from 30-40 Krag and 405 WCF. Remarkable, Buffalo Arms and Kynoch sell loaded ammo. I'll buy 5 boxes of Bertram cases and put them aside to future proof the Cartridge. The bullet selection is outstanding to the point where cost is a non-factor.