Do you really need the steel sprockes, or could you use the aluminum ones from
IFI instead? they include spacers, so you can mount them out from the wheel a ways. You may need to tap threads into the holes in the wheels. I haven't tried to put the aluminum sprockets on the new AM plastic wheels, but the bolt pattern seems to be the same (6 each 10-32 on a 1.875" circle), so they should work.