I plan on riding my '85 thu the winter if I can. At times, temps get to single digits here (not counting wind chill). Manual suggests a 50/50 mix (good to 31F). Should I go 75% coolant and 25% water for the winter ? I just took a 50 mile ride w/her and ran great. Wanna make sure I got enough protection. Mebbe some of our Canadian brothers would know.....thx in advance...