Turned it down into an 8mm tip with a 10mm shank.
I don't have a metric transposing gear for my lathe so I used dies for the threading. Turned out pretty good I'd say.
Drilled and tapped out the carb body for the stud and set it in place with a healthy dose of red loctite.
It'll never "blend in", but it's plenty strong with the 10mm-coarse threads holding it in place. Scrounged up a crusty 8mm nut from my spare hardware bin since it had a bolt in it before and therefore no extra nut. After it sets thoroughly I can continue with my carb rebuild.