The well-nut attachment method is really pretty slick. I was skeptical at first but after some testing I found the mounting method to be superior to what I was using in the past. Drill a hole in your airframe the OD of the rubber well-nut and install that piece. Thread the screw through the rail button and tighten down. This sucks the nut which has been vulcanized to the neoprene housing tight to the inside of the airframe - much like a molly wall fastener does in drywall.
If you're concerned about the drag from the neoprene flange, trim it flush with the rail button using an X-acto type knife.
Don't buy just one set, get a couple for the range box.
Also available in other sizes, see the website.