Funny! I had just edited my post to put in the same link that you found as well.
BTW: The pre-gen ninjettes used to come with 120 width rears stock way back when. Those tires became harder to source, so they went to 130 width, but didn't change the rim size at all (width or anything else). So the bike was initially designed for a 120 width anyway, though the slightly wider 130 didn't hurt much. (and given the crappy tires that went on those bikes stock anyway, it would be hard to judge how much of the lack of performance was due to the tire width compared to its compound/tread/etc.)