They make a metal strap specifically designed to hold the tailgate. It's like $70 for the pair, but I can't remember the name of the company right now.

I've seen the tailgate cables break before, and don't trust them...even new ones. I just use extra cargo straps.

 

I don't thiny you will have a problem, but if it were mine, I think I'd put a sheet of 1" plywood under it.

I also now only use endless ratchet straps. Hooks can pop off if things get jossled around, and the rubber eventually comes off and they will scratch things.

 

Found it !!!!! I've been thinking about getting a set of these, but I rarely haul either of the quads in my bed anymore.

DG Manufacturing Home Page

 

That looks like a good idea.