Hi. I am going to get an EOTech 512 for one of my AR15 flat-tops with a ARMS flip-up rear sight and solid front. I dont know much about EOTechs. I tried reading somethings on cowitnessing, but am not completely familiar yet. Some questions I have: -What mount should I get if I want absolute cowitness? -What mount should I get if I want lower 1/3 cowitness? Thanks.