I agree that it's a mistake to tune to temp, as it depends on the age of the engine and the conditions, but it's good to get you in a ballpark tune. As for the oil, I have to disagree for the most part:
Who knows why it happens, but I've noticed something similar to what Zipty533 is describing. Watching older videos of well-tuned engines from a few years back show more smoke coming from the exhaust. Whereas now looking at other well-tuned engines, very little smoke comes from the engine, and temps are still within a safe range. I'd say it has something to do with cleaner-burning methanol, oil and nitromethane which doesn't create as much of a smoggy smoke, rather a cleaner, wispier smoke.