Here's my Aimpoint compC3 on an Aimpoint gooseneck and a QRP mount. There's no way to use a cantilever mount on a carry handle upper, for as I understand it, the cantilever goes up at an angle from a flattop upper, whereas the gooseneck starts at the carry handle and goes down. (i may be wrong) But that's if you are mounting it on the upper.
If you have a solid free float handguard with a rail that is co-planar with what would be a flat top (even though you have an A2), then you could just use a straight mount, like a high ring.
the problem with trying to co-witness the micro dots on a carry handle rifle is that the rear sight gets in the way and you have no room to look through the tiny tube. You can't fold them down like a BUIS.
I had a micro on the rifle below and took it off. i replaced it with the 30mm aimpoint so that I could have room to see through the tube without the rear sight cluttering up the sight picture.
In my opinion, micro dots work on a flat top upper with a fold down rear sight or maybe on top of the carry handle with a low ARMS carry handle mount (old school)