It's been my experience over the years that measuring the overall coolant level in the bike by looking at the level in the overflow reservoir is not the true indicator.
Best indicator is to pop the radiator cap, and making sure no bubbles are at the top, assess the level in the neck of the radiator.
If it's to the top, then simply bring the overflow tank to capacity and call it a day.
Naturally check for leaks, and where the missing coolant went, but generally, some loss in the overflow is normal to me.
As far as replacement coolant: I searched high and low and could NOT find a specification on Kawi Coolant requirements, so the last time i replaced the OEM green stuff, I went with Kawi Branded OEM (green stuff) again. Not cheap@ $15 qt., and not pre-diluted, so I had to mix it, which I find - annoying.
On that note: always dilute coolant with DISTILLED water, when using 100% coolant. This is important so as not to introduce hard water contaminants into the aluminum environment of a radiator and engine, which can cause premature scaling, deposts, blockage, and failure of the internal cooling system.
Next time, if I do it myself, I'll opt for some of the Honda long life low borate / low silicate 50/50 premix that can be bought at any Honda Automotive Parts Department. Cost is about $12-15 Gallon, but this is the LONG LIFE stuff, and will last up to 5 years.And it's a pretty cobalt blue. Why Honda? I've used it in other bikes and cars -- it's just what I know.
Other brands make a similar blend, like Toyota and Nissan.
There's a good thread on the maintenance discussion board from SIS about his cocktail of water wetter for summertime, and what you choose to run in your climate and riding scenario is up to you.
you can't go wrong following the Manual with Kawi fluids though.
good luck. And let your NOSE be your guide when "sniffing-out" coolant leaks.....they Always smell like really hot, sticky, sryupy sweetness around the engine. And then there's the trail of Flourescent green liquid...

gr
**And what JWS said about "magic" coolant loss via the engine -- but if it's a minimal amount, say 1-3oz per year, then really nothing to get worried about**