Can you get access to the Platt's daily cash market postings; Bloomberg has them as well - look at the daily Gulf Coast refining metrics. I like the Bloomberg Crude Netbacks function ( what you really want is like a cash forward crack spread curve ).
__________________ Spread, Relative Value, and Correlation Trading Instruction from a Professional Trader. The only thing that matters are Clients making money IN LIVE MARKETS. Why not interview my clients for yourself on an independent basis. My typical client is an outright directional trader looking to pick up an industry-recognized specialty technique. http://www.spreadprofessor.com