If you already have the dished side of the sprocket facing outwards, the only other alternative is to use whatever is handy to act as spacers between the sprocket and the outer rubber ring. Common washers and/ or 5/16" nuts come to mind.
I did away with the whole headache and went with a MM clam shell adapter. They are worth every penny! Sgt.Howard sells his version, Sportscarpat sells his version, Pirate Cycles sell a MM version too. Any of them are highly recommended .