I have put West Coast truck mirrors on two winches. I would not be without them, I even put a light on shining on the winch for night work. They are supported on each end by brackets from the frame or winch end frames, holding the mirror laterally high enough to see into it from the drivers seat over the hood. They can be removed if desired, but we leave them on since these are work trucks. I as a rule detest convex mirrors because of the distortion. As the winch winds in, I let off the brakes allowing the winch to pull the truck enough to make steering corrections to crowd the cable as appropriate for a level wind.
Regards Marti