I know you’re well on your way down this path, but I saw this at work and thought of this thread. This thing, with a custom die, a pneumatic cylinder of about 8 inch stroke, and a manual air valve would cut out your parts faster than you could toggle the lever on the valve. Maybe rig the lever up to a reciprocal saw blade that also drives a set of feed rollers, and go full Rube Goldberg. Ofc, you'd have to source that stuff, but something tells me if anyone could, it’d be you.