Recovery board mounting options: side mount, vertical or at an angle

Thanks again for investing your valuable time to read this: I have FrontRunner racks on my Taco and I need a way to mount recovery boards on the passenger side of the rack. The top of the racks are already spoken for, full of other equipment: water heater/propane tank/kayak/trolling motor. I need a mount that resides outboard on the passenger side, either vertical mount, or at an angle. I have searched the net but can find only mounts that will attached to a round rail, not the flat surfaces of the c-channel of a FrontRunner rack. Am I looking for a unicorn, or are there such options out there? THANKS!

 

You could try something like this but vertically on the side. Basically I ran a couple bolts though the rack and then made mount of sorts with an eyebolt, washer and coupling nut. If you can run a bolt through the side that the boards can slip over then use the coupling nut to tighten down it might work. The bungee isn't necessary. It was just something I was experimenting with.