Why not just buy the winch now and use it for getting your dimensions and mock up?
You may want to change your plans on your bumper design once you have it on hand, I did.
I also picked up a smittybilt hawse aluminum fairlead for mock up just in case go to a synthetic line later. It is the same bolt pattern as the m8000 roller fairlead. You will want the winch with the line on it to determine the set height of the fairlead anyways.
Here I was using the winch and fairlead to determine how high to put the fairlead mounting tabs.