Water pump maybe?
Mike, when you parted out your machine, did you save the water pump which was mounted on the motor as well as the pressure(water level) switch? If you did, then the 12 in question can be convered to a pump drain which makes it much more versatile.
Also, if you cannot find any door gaskets for the 10/12/14/ series, you can use the ones from the 15-16-17 series as they are the same just longer and can be trimmed as needed.
As a last resort, you can use the WM series commercial gasket from your Hobart dealer. Part number is 121030-2 and are available for 19.70 and get some new gasket clips, part number 24677 which are 2.00 each and usually came 6 to a bag.
Hope this helps