How about a custom die for an iron worker? Stick it in, hit the foot peddle.
Next.

I'd be worried about a convex cutter with stainless. You'll need quite a bit
of material sticking out if you one pass it. Sounds like not rigid enough -
chatter - work harden - break cutter. Just a guess.

Don't know if I'd want to do 1500, but circular interpolate in CNC mill
would work. Make fixture to hold several. This would take some creative
work. One at a time would take forever. I've got an air actuated vise, you
could do two at a time in each vise and have several vises on the table.
Operator could change out while machine is on other vise.

Karl