Depending on whether those 2 options are quarterly or serial. if you got quarterly then you settle into cash and, essentially, it is the same as 1 SPX option. If the 2 options are serial, say Feb as in example above, then you settle into the Mar futures contract and it is not the same as the Feb cash-settled SPX options. But in general, given that 1 SPX point is worth $100 and 1 ES point is worth $50, you need 2 ES contracts for 1 SPX contract.