Both 40-60 WCF and 45-60 WCF are based on the 45-70 case.Length is shortened to 1.890.
40-60 Maynard is .303 Brit or 30-40 Krag blown out straight.
For me,the COW trick....with NO BULLET works fine but I use Bullseye.
I'd suggest virgin brass or annealed necks or they might split on you.
I'd think 40-60 WCF is hard to come by,and would have trade value.
45-70 is current production . I'd rather neck down than up.
FWIW, a while back I ordered 300 BLK from Starline. Web Page said "Out of stock/backorder" I backordered. It was delivered in 3 or 4 days.