Once you remove the factory sheet metal inner fender liners, you will see a metal lip that is stamped into the wheel well. The new inner fender liner that is welded to the end of the slder (1/4" thick) rests underneath this lip. You then drill 3 holes and through-bolt the plate. That way, not only are the 3 bolts supporting the end if the slider, but the top of the plate is resting against the stamped lip, preventing the slider from being pushed upwards.
I hope that made sense.
By the way, the group buy is over and all have been delivered. I can no longer honor the original group price (due to increased production costs), but I can offer a discount from the normal price for anyone that refers to this post.
Thanks again to all that participated.