i think it is best to not use any less. I don't know if sno pro has higher compression heads, but if it does, then yes, nothing less, if it doesn't you can get away with less but i wouldnt recomend any more then what is needed to get you back to the truck or a pump that has "good gas". I used 87 in my rmk once because i was out and a long way from the truck, i noticed a big dif. If i can at all help it, i wont use that low anymore. Also, higher octain runs cooler (exaugst temp) not a bad thing.
Too low of octane and a too rich jetting will burn a hole in the top of the carb from pre-detination. Polaris said they wanted the XC when they 1st came out to run low octane fuel and later changed thier policy. Get as high of octane as you can get ALL the time. shane