I have done a 4-12 swaro, 4-16 4200, 3-9 4200, burris ff2 in a couple sizes. I like the size of a 40mm obj. I like the fov of 9ish power on top. I use my Roy to stock pile coyotes, deer and have taken elk with it also. I really don't need much magnification over 9-10x for anything other than paper over 500ish.