[EricH]

Originally Posted by furiousgeorge

do you know if the fabric has to cover the entire back side of the bumper, or is it acceptable to have a small a mount of plywood visible? we left some open for our blind mount attachment sites.

The rules don't say explicitly, but look at Fig. 8-1. Yes, I know the images aren't supposed to be rules, but...

The red line represents the covering; note that it stops short of covering the entire back side. You should be OK. I've seen lots of bumpers in the past that weren't fully covered, under the same specs for building.

If you still aren't sure, ask Q&A directly.