When you say "Natty is usually backwardated in the winter and in contango in the summer" does not pertain to a particular contract at a particular point in time?...I'm probably be a bit nit picky, and this is really just a "am curious" question, but am just trying to understand if a specific contract being in contango/backwardation at a given point in time is a 100% objective measurement based on it's relationship to some other contract (usually the spot month).
Do the work I recommended earlier ?
Maybe the answer is yes, maybe no, maybe back/con doesn't make sense for a butterfly ... maybe. Just asking.