I just bought a TA01NSN with TA51 mount from a friend who had lost his manual a long time ago, so I'm wondering if there is a certain rail on a picatanny to mount for optimal clarity or if it is all a matter of preference. Currently I have it mounted so that the eye piece is about flush with the charging handle (you can see the 1st rail and the last 3 towards the front). I won't be adding a BUIS or anything and if it helps it is on a Stag 16" flat top upper. Any and all info/opinions from you guys would be greatly appreciated!