Please email us at techsales@opticsplanet.com for further assistance as it will depend on the make, model, and caliber of your rifle.
I have the same scope. If you have an all flat top rail such as an AR, the lowest you can go without the Objective Bell touching the rail will be the 1.125" rings, which clears the top of the rails by 0.075 inches. If your rail is short and raised, like a scope base on a bolt action rifle, go with the 1" rings, which the objective bell will dip below the top of the rail by about 0.05 inches.