Have not used gatorback, but have been very happy with this product from BassPro Shops: http://www.basspro.com/Tie-Down-Self-Centering-Bunks-GlideOn-Covers/product/52357/#desc-tab
The picture of this product is somewhat deceiving. What you get is (4) pieces of staple-shaped plastic covers that attach with stainless screws to the edges of the 2X4 bunks (not the top of the boards). Each piece is 4 ft. long. Each piece has a squared-off end and a rounded-off molded end to protect the 2x4 bunk when you drive on or off. The glide-ons have molded-in grooves that really do force the boat towards the center. In my case, I had 9 ft. rotted boards that I replaced with new treated boards. Then I attached two 4 ft. glide-ons to each board which left a 1 ft. space in the middle. I covered the one ft. space with standard bunk carpet. Been using the glide-ons about 5 years with no issues - one of the best things I've done to help trailering my 16 ft. aluminum Bass Tracker.
In memory of my childhood friend Dan Sterling, who taught me at an early age how to catch bream with a hand-line, and who unknowingly hooked me on fishing for life.