I have the Primary Arms Micro Dot Gen 3 with Killflash and the "Emergency Release Lever" (not quick release) riser. It does not lower 1/3 co-witness well because the emitter is at 6O'clock and sticks up too much. You can see the very tip of the front sight post which is enough to operate but if I was buying over again I would not buy the PA riser. I would buy the Larue HK mount. With the HK mount you have an absolute co-witness and a release lever that actually works. The HK mount is pricey... about $70 more than the PA. To show you how high the PA emitter is up into the sights I flipped my MBUS around backwards and put it right up against the Micro Dot. See the emitter up into the sight aperture.
PA aptly names the lever as an "Emergency Release Lever". You'd really need some type of emergency to pry that thing off. Most cheap Chinese release levers are less than impressive-- PA is no different. Mashall (the guy who operates PA) posted on another AR forum how to grind off part of the lever so it will actually work
. Marshall is a real good fellow and is up front about all this. In fact, he ordered the Larue HK mount to see if it would properly fit on the Micro dot and co-witness, and posted so on another AR forum.
Please excuse the toes... it was an early morning photo shoot.