So I purchased picatini <sp> riser block, and a cheap Green Dot scope today. I'm not sure what the difference in green/red is. Is there any tactical advantage to one vs. the other? Also my main question: Where to mount it. Between the length of the picatini rail, and the the length or the riser block, I can adjust the eye relief by about 4 - 5 inches. What's better tactically? Should I have the scope mounted as close to my eye as possible, as far away, or somewhere in the middle? I've tried it mounted very loosely all three ways and can't see a major difference. I don't want to tighten it down until I've decided, because the gun has that stupid 'mossy oak' film on it, and I don't want to mare it unnecessarily, if I don't have to.