Are you wanting to cook them or keep them raw in the shell with a smokey flavor?
I have done both, to keep them raw keep your temp as low as possible and place the oysters still in a half shell on a sheet tray covered with ice. I did that for about 45 mins and was constantly opening the lid to ensure they did not cook.
If you want to cook em, that's easy should only take around 20-30 mins at 250.
I used apple and they were tasty.