I was not suggesting to use water alone. My point was that the charts show that adding WW (or PI I guess) has little additional cooling effect, and therefore is an unnecessary additional expense. There may be other benefits not shown on the charts and since I have not used the stuff I cannot comment on that. Other that optimizing the mixture ratio as you suggest, the only thing I think would be useful is to keep the radiator passages free and clean.

Best regards,

JL