This is the link to the AndyMark Cad file, which clearly shows the sprocket mounting holes to be 3/16" (.1895).
http://lib.store.yahoo.net/lib/yhst-...lick-Wheel.pdf
The tap size for a 10-32 is about 5/32" (75% thread clearance), clearly smaller than the existing hole in the wheel. It would seen to be far better to open the hole slightly for the #10 bolts to go through, and jamb nut the bolt/sprocket /wheel assembly together. #8 bolts would be too sloppy in the existing holes (maj. diam. of .164").
