Thanks but it was a royal PIA.
That piece of plastic I made the valve out of probably doesn't seal as good as it should, but it was the only thing I had around that somewhat worked.
I got another used valve - looked inside - its also missing the valve tip.
Bought a similar new replacement valve, wrong size hose connections.
I didn't even try to recrimp mine. This way I can just cut the tape off and replace the plastic valve if/when needed.