I use 2 cans of Water Wetter, water and aprox 1 lt of anfifreeze (to help inhibit corrosion) and a 160 t-stat. It rareley sees the high side of 200 on a hot day (95 deg or hotter). Usually runs 180-190 in hot ambient temps, and 180 when is cooler than 80 degs out. Water will disperse heat better than antifreeze. Water Wetter helps and inhibits rust and lubes the waterpump.
Hope this helps