I made up some small alloy plugs that were shouldered to match the outside of the throttle body, I gave them about a Knats Foreskin interference and pressed them in from the outside.
I then trimmed and cleaned them up on the outside.
Edit;
A Knats Foreskin is a tool Making term.
A Knats Foreskin is smaller than a Knats deck.
A knats deck is smaller than sweet F*** all.
Sweet F*** all is smaller than F*** all.
F*** all is about a thou