I think Honda missed the mark on the 919 and sized the radiator on the small side.[/QUOTE]
The 919 rad is indeed undersized for sustained full power use on high ambient days. But, this should only display itself on a track with lots of full throttle full load time, or on a dyno. If you are seeing past half gauge on the street, something is wrong, be it coolant, pump, stat, fan or rad related. In hot climates, the classic 50/50 mix is part of the problem, as it has a very poor specific heat characteristic as compared to water. All the more reason to be using Redline WaterWetter or equivalent.
An oil cooler would be wise on a turbo setup, but nothing else. Keep in mind that your hot cooling system heats the oil as much as it cools it !
You live in Georgia ?
What's the coldest temp your bike could see ?
My guess is that you could easily go to a 75/25 water/ glycol mix, maybe even 90/10 if you park in an attached garage in the winter. 75/25 would give you freeze protection down to about 11 F and it can't actually freeze below that, instead, is slushes up. 90/10 covers you to about 25 F but at that ratio you are on the ragged edge of lower temps resulting in a solid freeze as compared to slushing up. The 10% cut of glycol is really just for water pump seal lubrication and some corrosion control. ALWAYS use distilled water, never tap water. To be clear, glycol is a lousy cooling fluid ! It is essentially used for its freezing point characteristic, while providing an acceptable, not desireable, heat transfer characteristic.