[MadMax]

IMO a sniper rifle doesn't really match with a RDS which is meant for rapid target acquisition at close ranges. You've got a long gun, it's not really meant for a no magnification optic which is meant for rapid aiming with an easily pointable weapon.

That being said, whatever turns your crank.

There are some technical tradeoffs to mounting a RDS further from your eye.

An RDS mounted close has a larger field of view through the RDS lense because a greater angle is included within the 1x lense. Also, because your eye is closer to the lense, the dot will appear larger and brighter.

However, you lose horizontal or vertical displacement from the centreline from which the dot is visible. A RDS projects a dot within a somewhat narrow angle (say 15deg total angle/7.5 deg from the centreline). This means that increasing the distance from your eye to the optic will allow a greater distance from the centreline from which you can view the dot.

I find that a RDS mounted further to the front puts more RDS frame close to the centre of my aimpoint which clutters my sight picture, but the dot is very rapidly acquired (if it's a bright RDS). I find it works well in CQB situations because of the large area of acquisition.

However, for more carefull shooting, I prefer to bring the optic in close to enlarge the RDS frame further from my aimpoint and free the centre of my aimpoint from frame clutter.