Hey Mark...Sean K here...good to hear from ya, and thanks for all the pics and examples of this. I've done this to several games over the years and I agree...it works very well.
I had a badly warped Olde King Cole PF I installed one of these on, and the pics are below. Funny thing is after I did this, the PF reacted by warping more in the middle! I installed another angle iron in the middle, and it was better, but then I found a beautiful spare PF and replaced the whole thing...figures! LOL