Did you ever try running the blend without heat? I am under the impression that I could run that 50/50 blend at really cold temps without any heat.

Quality of oil is an issue. We say WVO but it can mean anything. If it is oily and dirty it is WVO. I am going to start filtering my oil after it sits overnight in an old spare refrigerator. That way anything that gels down to about 33°F will get separated out.