Folks... I've decided I'm going to invest the time into the recommendation to put a tab on the back side of the deflector (thanks @pballinreno). I think its a good idea... and if nothing else it will put to bed the question of whether or not this thing will hold up over time.
Beyond durability ... as I got into analyzing it.. the rear mount will also prevent any upward motion on the deflector... which is a good thing for two reasons.. 1. consistency of the performance of the design and 2. it will make a better protector as it will eliminate flex on the mounting tabs.
Thanks for your patience and feedback. Designing stuff in an open forum is good... except ... well you know.. tweak, tweak tweak. In product development there is a standing joke where we sometimes have to take the product away from the designers so we can ship it... even if its not "perfect"
Seriously... thanks though. You all will be pleased when it is completed.