[EricH]

I think y'all need to re-read <R07>. The 6" minimum is length per segment (<R07-D>); the maximum of that dimension is as long as the robot. You need a 3/4" thick x 5" tall piece of plywood as bumper backing (<R07-F>).

I'd also be cautious about the plywood in the corners--because you're changing segments, you may run afoul of <R07-C>'s corner/segment joint-filling rules. In the past, it's been much clearer about whether or not hard parts in corners is prohibited (it was in the past, not sure about this year).

Note that these only apply to the bumpers that are out in the Starting Configuration. Ditto for the extra bumper weight allowance.