I agreed, I have the Dowco Guardian cover for my bike. I believe it is the medium. I don't really remember what their size was, but it fits great even with my luggage on.
I bought the cheap cover on ebay for the 6R. While it does fit the bike, it really isn't much protection other then keeping dust off the bike (which is fine, it is garaged). Next time I would buy it a little larger. It fits tight, and I prefer the Dowco cover on my BMW, it is larger and easier to get on and off since it fits loose. If you go for the ebay cover, buy it 1 size larger then what they suggest for the 6R.