With a few exceptions, the difference in total fantasy points between good kickers and average kickers is teeny tiny. Their performances are effectively random, and even out over time.
Opposition isn't always a a good indicator. Sometimes kickers thrive against tough defenses that prevent TDs, forcing their teams to kick FGs. Other times it means the kicker doesn't get opportunities. Same thing with bad defenses Bad defense means its easier to score when you're down there, but it also means you get down there more often. And extra points do add up.
Personally, I'd stay with Longwell. But don't sweat it. Odds are kicker decisions won't win or lose you many games.
