I scalp the ER2 contract. I am looking to spread ER2 against ES. I am curious if anyone has any ideas on the correct spread ratio. ER2 tick=$10 point=$100 Average True Range(30 days)=13.5 ES tick=$12.50 point=$50 Average True Range(30 days)=13.6 Am I correct in thinking 1(ER2)-2(ES) ratio is the correct spread ratio. Any thoughts are greatly appreciated.