I have had the same questions for the past year, and still don't have a correct answer from everyone. I will tell you this though, There are multiple guys that run tapered lug nuts, then a plate on top of that, then 5 more nuts. It satisfies the rule, because no where in the rule does it state you cannot do this. From my understanding the rule is in place for thin, 2 piece wheels that are made to have FLAT washers and FLAT nuts, like the original centerlines. I will also say there are a "few" cars that get passed by tech that have cast wheels, with a conical seat lug nut only system. We ended up having to make the wheels "hub-centric" and running a 1/4" steel plate over the tapered lug nut holes.