Like I said I don't think the washer fix will work for you. Not so much due to the shortage of threads though that is a serious issue, but because of the type of drop outs you have won't allow you to align the rear hub to a location that will allow proper chain alignment of the rear sprocket to the engine sprocket.
If you look down the face of the rear sprocket I believe it will be lining up at or near outside of the engine. Since your axle has to be in a set place the only simple way you can correct this is to move the rear sprocket inward via a top hat. That is what I'm getting from your pics. The sprocket has to set inboard of the face of the rotor mount.