Thanks Gary and Felro86. I think I'll just buy 5 packs of the 91187 that Gary recommended. I can't see why there would be a significant difference in lug nuts meant for aluminum versus steel wheels.

 

The difference is the depth of the wheel. Aluminum wheels are thicker, so the threads need to be there and be strong deeper in the lug nut, while steel rims don't necessarily have to runt he threads so far down. Factory aluminum wheels use the taper, but some after market aluminum wheels used shoulder nuts.