Well I looked up their winch, if it is the same one you have, it has a 1hp motor. The calculated FLA for a 12VDC 1HP motor would be close to 80Amps. 746W/12V=62.1A, 62.1A/0.8=77.7A(Efficiency Losses). To calculate fuse size the rule of thumb is 135-150% of motor FLA, rounded up to next standard fuse size. So 77.7x1.5=116.5, which puts you at about 125A fuse size. Any larger, and it won't offer overload protection, only short circuit. Now, you have a 250A in there, that will barely offer short circuit protection, because it will force your battery to supply more than 250A for a rated time period to blow. I would suggest a 125A fuse. A basic automotive blade fuse will work, or glass fuse, like you see in car audio.