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)