Coolant Type

I use a good 50/50 mix..There is nothing wrong with water.

Heard some bad things about Evans waterless.
 
Refractometer
Back when we all had the sage words of Wayne Tripp to rely on - I asked him about Evans.
He suggested I did not bother.

Good water/antifreeze mix and DEI Radiator Relief.
It works well.

The weak point in the R3's coolant system is the pump. It causes fluid cavitation above 4000rpms. It's a common issue in many water pumps - iirc @Claviger was looking for a way to upgrade the design.
 
If it says HOAT on the bottle somewhere then it is compatible and recommended by Triumph.

I would just top up and wait until next year to replace.

Is hybrid OAT a mixture between OAT and silicate?