I read pretty much all of them he wrote and would say it isn’t worth it. Never been more frustrated reading books, but it is really good world building and usually had good endings

PSX refining capacity is about 2mmbl/day or about 84 million gallons. Q3 earnings were $3.1 billion. So a very rough total margin per gallon on all products is about $0.40/gal. It’s much lower on that for fuel though