Nice work on the testing, paper io you’ll get much better consistency and sabot survival if you switch to a tougher filament like PETG or nylon and start gluing the fins directly instead of relying on a press fit.

Those look like older industrial solenoid valves with pilot boxes, so they could work for pneumatics if the seals are good, but they’re bulky and might sell better on eBay to someone needing replacements.