Thanks, that's very interesting.
Personally, I was never under the impression that "bracing" was done to "provide installation support and security" (other than the
theoretical benefit of preventing over-rotation in a collision). By that I mean, I've never heard anyone suggest that an unacceptable install could/should be "corrected" by "bracing" with the front seat. Along the same lines, I've never thought that "bracing" should be used to adjust the angle of a child restraint. In my understanding, "bracing" simply referred to firm pressure from the front vehicle seat, AFTER the child restraint was correctly installed. "Bracing" would have the seats touching hard enough that a piece of paper could NOT easily be pulled between the seats. Usually, there's one "click" difference in adjusting the front vehicle seat, from "lightly touching" to "bracing" (in my mind) but either way, the vehicle seat would be moved
after correctly installing the child restraint.
Maybe other people use the term "bracing" differently than me...???