I used the Insight MRDS on a Wilcox mount ontop of the 2.5-10 on a Mk12 alot which got me into liking the RMR on the TA33 ACOG (not the 4x, that one has the worst eye relief on the planet).
I don't like the 45 degree/angled offsets. If you drill alot on things like up drills (fast presentation on target) as well as multiple shots on multiple targets where you need to move your torso and/or stance the 45 degree hold you need to make changes your grip, recoil management, shoulder/head position rather than simply training on bringing the rifle up the exact same way on your torso/shoulder from a low ready and simply adjusting your eye position for the sight you want to appear before it.
I do with this the ACOG often and drill both to where if I want the RDS on close up targets I bring the gun up 100% the exact same way as I would if looking through the 3x ACOG, only difference is my face tilts slightly forward for the ACOG and is at its natural rest position for the RDS.
Other thing to consider is why put a optic and RDS on a 11.5 gun? My 11.5 KAC has a KAC M110 riser on it and an EoTech to allow for passive aiming with an ANVIS9.