It seems that the entire aftermarket agrees that 120 is a fine tire for this bike. Literally the only reference I've found to 130 is the honda owner's manual. Most of the "what fits my bike" and recommended-pairings for it use a 120/70 and 190/55 set. ** shrug **
To expand on tire sizing...
Mine has a pair of 120/70 + 190/55 Pilot Road 4s on it and handles like a dream. The minor size differences aren't enough to affect the profile to the point of any real world differences. Just buy regular sized modern tires and put zero more thought into it.