It appears to me that you would need the large. If you would measure across each of the cupholder openings I could tell you more. There is a sizing chart on my website. I will be glad to help you further once you give me the measurements.
Tim
cupholder inserts for CX-7
I would like to suggest a product that I invented for just these reasons, it's called the "Drink Docker" you can find it at www.drinkdocker.com and find out even more at www.rav4world.com I hope this may help
Thanks,
Tim