Maybe I'm missing something with the fuse sizing.
Every electrical circuit I've worked on has always been sized the same way for fuses or breakers.
You take the wire size and protect to the amperage rating of the wire.
That way you get the minimum amount of nuisance tripping or blowing fuses and it'll pop on a short circuit.
I would be annoyed if the only thing that stopped me from getting out of a hole was an undersized fuse because I hadn't tested the winch at an extreme recovery. Just because it holds in flat ground in snow doesn't mean it'll hold in a mud hole or on a steep slope after ten minutes of intermittent winching and everything getting hot.
Please correct me if I'm wrong and let's try to stay civil.