I was planning on tracing using a paper diagram, scoring with a knife, and then cutting with scissors. A compass mounted knife would be ideal, but my compass isn't big enough, and mounting a knife to it would be a DIY project in and of itself. Not sure what I'd do for the holes inside the discs; maybe either melt them or puncture them carefully.
My wheels are the stock wheels from the EX trims of the 7th gen civics (image from online, not mine personally; I don't have mud flaps.
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What advantages would cutting out one single hole have? My current plan is to tape over those small holes and see how that holds up.
Yes I'm hoping so. Right now with just hypermiling and tires inflated to ~38 PSi I'm now getting around 40, give or take depending on drive and conditions. I think 50 is doable for both of us.