On a Rating,
My rule of thumb, double the laden weight of your rig.
Then find a winch unit at or above that number.
Also make sure all your slings, tow straps, snatch blocks are also above this rating.
And a little often winching mistake:
IF YOU ARE USING A "SNATCH BLOCK" TO A LAND ANCHOR.......
The equipment AND THE TIE OFF POINT has to be able to hold DOUBLE the laden weight you are trying to pull !!!!
CAPT