Learn to use both eyes go through some marksmenship principals when you find yourself closing an eye.. I guess I'd be left eye dominant but right handed.. Me personally learned on c7 with the c79 optical and then the c9.. Its not totally wrong to close an eye either just don't keep it closed because in sniper/dmr role you'll develop tunnel vision and you'll always get shot from the side your eyes closed lol.. In an assaulter position always 2 eyes open when room clearing or cqb because you'll depend on your peripheral vision.. Also find position is also important when taking up a sight picture wear low profile goggles if possible.. Just my 2 cents
