Saw your other question too, but didn't have an answer still.
They're moderately large however, so I'm thinking at least a #10
Guessing you don't have a supply of them in various sizes just laying around your garage waiting for you to try?;D
Luckily this particular location does not strip out as often as some others, so your holes will possibly still accept the original size. Now if someone will just pipe in with that info, you can get 'er done.
Good luck.
Paul