I have an FN SPR XP .308 on the way and trying to figure out which rings to order. I will be mounting a Vortex Viper pst 6-24x50 FFP on it. I really like Larue mounts but the 2 choices are 1.28 inch height or .875 inch. Wish they had something in the middle. What other brand rings would you recommend? I'm looking at the Nightforce ultralite rings (medium). These are 1 inch height. Thanks for any help or advice.