I flushed mine with water several times and then added the coolant and flushed some more and then topped it off.
I'm using the Toyota Red after researching the specs and because it is easy to get in oz.
It sounded like you had heard of problems. It is the OEM coolant that Triumph recommend but not available in my neck of the woods. Its blue/green depending on the light.
But I doubt its going to be any better than the other well know brands that meet the specs.