The tighten until it strips and then back off 1/2 turn is a joke and I DO hope you didn't take me literally. HA

As to the nylon bolts and the blind nuts, I am assuming that the blind nuts you mention are the metal type and not just a treaded piece of wood block that many kit makers use. I usually install the metal blind nut if that is the case because threaded wood blocks wear and chip off the threads. The other thing you should note is that metal blind nuts are machined (use that word loosely) and the nylon bolts are molded to loose tolerances so my best guess is that you may have a nylon bolt that has changed shape since manufacture.

Some folks don't like nylon bolts for wing hold downs because of the possiblity of the bolts breaking off (over tightened), they still like to use rubber bands. Personally, I like the bolts for a cleaner look. I guess if I were really concerned I would switch to a metal bolt, smaller in size (for weight consideration) and put a washer under the head for larger surface contact on the wing. How bout that! Then tighten away.