Congrats on your new Colt carbine, you won't get disappointed by it, they're very reliable in my long 42 years experience with Colt AR rifles and carbines. I'm also a long time owner of 24 years of Aimpoint optics so that's my preferred brand.
Currently I have two Colt 6920 standard model carbines, my second one I had installed a Magpul MIAD FDE grip and Magpul STR FDE stock it handles great better than my other one with the military M4 furniture in my own opinion.
I'm using an older model Aimpoint M2 for eight years now without any problems, it is the same outer dimensions as the PRO model except mine have a shorter battery life, I'm using a LaRue Tactical cantilever model LT129 QD lever mount because I sometimes use my magnifier behind my dot sight.
If you're not going to use any magnifier or night vision optics behind the Aimpoint just get the standard LaRue model LT150 QD mount, most all their mounts are lower 1/3 co-witness and are very robust in construction, also unbeatable return to zero performance.
Also if you want to get the LaRue mount and want to save a little money get both the optic and mount from LaRue Tactical they offer them as package combo deals, they're more expensive if purchased separately.
About the T-1 Micro, I have friends that have them and are nicer, smaller and lighter but at extra cost, if you prefer them and don't mind the cost also get them with LaRue QD mount.
http://www.laruetactical.com/aimpoint-pro-patrol-rifle-optic-w-mount
http://www.laruetactical.com/aimpoint-micro-t-1-2moam4-qd-mount-combo