1) I've given up on worrying about mileage changes on GC. Any variations that I've seen have been too small to matter. Both of our vehicles (a Sequoia and a G35 Sedan) get absymal mileage, and an mpg or two one way or the other isn't going to help me much.
2) About a year ago, when I was still deep in the initial throes of GC fascination, I tossed a couple different quarts of oil into the deep freeze, including one of GC. The only one that got gruesomely thick was the Havoline SAE 30 that I had on hand for the then-new generator. The GC, like all the others, got thicker, but not alarmingly so, at least not to me. OTOH, I don't live in a climate in which I worry much about cold starts ever. Patman, another GC user, would seem to be much more qualified to speak on that. Pat, any startup issues you've noted?
2) About a year ago, when I was still deep in the initial throes of GC fascination, I tossed a couple different quarts of oil into the deep freeze, including one of GC. The only one that got gruesomely thick was the Havoline SAE 30 that I had on hand for the then-new generator. The GC, like all the others, got thicker, but not alarmingly so, at least not to me. OTOH, I don't live in a climate in which I worry much about cold starts ever. Patman, another GC user, would seem to be much more qualified to speak on that. Pat, any startup issues you've noted?