sight it in and see how it works, i think that it will work just fine seeing as the acog can mount on an a2 ar15 carry handle which is just as high if not more. they design the c variant for the option of having a diverse range of sights and optics. there is no one set optic designed for a g36 other than the hesoldt that i know of so as long as you keep the acog as far back on the rail as it'll go, you should be fine. the doc optic shouldn't add any more significant height. i have a ps90 the rail is super high and i have used the same acog and an atn red dot and an eotech all when sighted it work fine. the acog is killer cuz it holds zero, that's key.