Jerry,
I have Zippers Max Flow kit on my CUSE, I was reading a post earlier on high flow kits and the topic of the oem air cleaner cover is not secure using the Zippers kit. Yes i am experiencing that problom, It seem the flat spacer provided is not enough to get the job done correctly, I respect your knowledge on this matter for a guided solution. 
Tom
Tom, I wish I had one of the late model CVO covers so I could mount a round filter in it and take photo's of where you need to make modifications, but since I don't have one all I can suggest is that you take the filter element and mount it into your cover with the center bolt while off the bike on the bench (protect the outer surface of the cover). You will see that the end of the filter element only touches the cover at the top and the bottom, and the front and rear are sitting in space. You need to add something to the cover to make solid contact with the filter at the front and the rear. This could be fabricated from metal, wood, hard plastic, etc. and epoxied into the cover. Whatever you use,
the intent would be to make the contact points at the front and rear the same height as the contact points at the top and bottom. With the cover solidly supported at 4 points, the wobble and movement would be history and the chance of breaking out the center nut would be eliminated as well. Think of it like a stool, to keep from falling on your kiester you need more than two legs on the stool, and the best and steadiest approach is four equally spaced legs around the circumference and as far out from the center line as possible. The reason the Zipper's washer idea doesn't work well is that it moves all the contact and support to a small area at the center. If you tighten the hell out of the bolt, you can eliminate the rotation but you will still have a relatively small area supporting the cover and it will move if you press on the front or rear of the cover. Going back to the stool example, if you move all four legs in close to the centerline of the stool, you will find it very unstable and once again the odds are you will fall on your kiester.
Jerry