I blanked another wheel for a "smooth" MINI seven hole mod. Aerohead remarked once in a thread that the issue with these wheels is largely the higher pressure air working its way through the wheel to the lower pressure area behind the wheel. So blanking, even though not smooth like a disc, might provide a substantial benefit. I wanna see, if I can.
I think the foil & weed barrier may not hold long. If it does not, I will look for another method, maybe make a mold of the rim inside for a fiberglass piece?
To reinforce the foil, I sprayed four layers of clear plastidip onto it. Should keep water and dust/grime out of the tape seams. I might do that on the front, too, for same purposes.
Also, I arranged my Ultragauge on the flat instrument panel I installed where the drink holder used to be. It is flush with the panel so I can press the face of the gauge and activate the buttons on the back... Here you see it in mid screen switch as I depress the face of the gauge.