Aside from buying longer term futures contracts , there is no more contango to bleed USO. The declining dollar will reprice oil higher and OPEC won't make the same mistake twice. I would rather do the opposite of that trade until the end of the year.
what strange strategy. USO is as flat as a flat glass. price has been around $28 for donkey months. when you do spreading, you expect spread to widen or spread to shrink. In this case, why bother to do spread when USO price is so flat? why don't you simply long the unknown oil and unknown gas stocks? why add another complexity?
Considering the totally unpredictable value of oil right now, I would suggest you to rather wait a while.