The question has been asked as to which is better in the Crack Spread. Use the same month for crude and products ...or... use a one month delay for the products?? The attached shows the Dec 2011 Crack Spread useing the Dec. Crude vs. Dec. Products and Dec. Crude vs Jan. 2012 products. Comparing the two... a majority of the time the difference is less than $1.00 per bbl.
Do not use Dec 11 anything right now - I know that the distilled products roll later than crude, but quite frankly it is very difficult to account for the roll when you are modeling crack spreads. Quite frankly I am currently using the Feb contracts at present with the ICE Gas/Oil and the Nymex distillates.
1- The Dec 11 Crude contract stoped trading about 4 weeks ago. 2 - This was to illustrate how small the diff is.
The Spring and Fall refining run changes are much more pronounced in terms of heating to driving seasonal changes, and that is where your efforts would be relevant. Dec to Jan means nothing from a fundamental standpoint.