Re: Woodruff key No.# size
It seems likely that some vendors might stock that part too...
Just to mention; The proper key will be sized in metric, and must fit in the keyway and sprocket snugly. No glue or other goop is needed.
With patience, you can file a larger key to fit. Any play must be avoided as it will lead to damage of the keyways, or shearing of the key.
As I learned on this site, "pinging" of the key could be necessary to assure that it will stay in place.
Let us know what you figure out.
It's cooler to not fall off your bike.