Chef may be on to something here. While fender boards are typically used to bridge pilings that a fender would slip past, they also distribute the load across more than one fender. If you're have unusual pinning against your floating dock, there may be something to spreading it out. Often, one or two fenders take the brunt.
I put out six fenders, when only two take most of the pressure under normal conditions. I rotate which two are in that position, so they don't wear more quickly.
They way I do it now, I have use three of the Big B (10 " X 30"). One is horozontal tied off at pier and I have two vertical tied off at the base of a stanchion post on the boat. The one horozontal at pier would handle all impacts on its own, but I have two verticals just to help, and to take over in case the horozontal deflates.
This all works well, but as with any dock, there are eges that wear away at the fenders. I do rotate the fenders and change height, but after three years one has developed a leak- I think it is a defect (looks like an internal split) and will try to return for exchange. If you read the Taylor warranty, they do not cover wear damage- which you might get by rubbing, nor would they cover a puncture damage. Using a fender board could help by distributing the pressure points. The thought on the tires is they are cheap, would not deflate during a storm when you need protection most, and if they wear, they are cheap to replace. I see the down side however.