I applaud the idea of making this part, but without a lot of specialised kit I think you will struggle. From my experience as an ex Rolls Royce toolmaker/ universal miller I have made lots of bits over the lasr 30+ years for my supercharged x/flow Westfield, and even considered something along the lines you're thinking for my current TCS, but without either a broaching m/c or a slotting head for a universal milling m/c. you'll have a hell of a job on your hands. But good luck anyway. Just do it up tight!!!