Here is a suggestion (which I have never tried). On a hot, humid, high altitude day, your engine actually needs to run leaner to get the proper proportion of oxygen vs methanol. But it is hot and your engine needs to run cooler. So how about adding a couple ounces of oil to a gallon of fuel and leaving the needle alone? That would give you a little leaner mixture which ought to run a little cooler. You might have to fiddle with the proportions a little to get it right.