TRS 25 with High Rise - Coexists with M&P 15 -22

[SweetPotato]

I recently mounted a TRS 25 with High Rise on M&P 15-22 and wonder if it is suppose to 1/3 or 100% coexists. When I just look thru the RDS the back up sight is about 1/3 low. When I look thru the sight, the FSP properly align with the rear sight is dead on with the dot. Is that how they are suppose to zero or the RDS should not have been dead on with the back up? Thanks.

[NATEWA]

Cowitness and it's your preference

http://blog.primaryarms.com/2012/01/can-i-get-co-witness.html?m=1

[NATEWA]

https://m.youtube.com/watch?v=ogX-cIx9hpk

[SweetPotato]

Thanks. The video is really clear. I guess I have a 1/3 cowithness with the high rise.

Does this http://www.amazon.com/UTG-5-Slot-Ada...D7K655N75RJFDD UTG medium profile give me a absolute cowithness? I check its height but it doesn't make sense if it would or not.

[AreWeFree]

^Yes, UTG medium is 0.83" and is absolute cowitness

[SweetPotato]

The link above is 15mm = 0.59" so I assume it is for something else. And it should be this one http://www.amazon.com/UTG-Med-pro-Su...PC40DWHYJBTZSR which is 0.83", right? Do they make one with QD with 0.83" height?