Yeah, what Wilbur's trying to say is that you can't get perfect synchronized movement with AHK or any method to my knowledge. The issue is game latency, all of those little half second differences in reaction.

/follow is your best friend, you just have to learn to adapt your situations to benefit, and also break follow at the appropriate times. For instance when I'm doing... an instance... as I'm running up to the mob I'm going to tank I break follow on the 4 then pull back to them with my tank. If you hold aggro well then you don't have to worry about moving the alts at all.

Now when you get into fights where the main target likes to move or the scenario forces you to move the alts (Shattered Halls first boss, Ramparts last boss, etc.) then strafing will come in VERY handy. Basically strafe out of the dmg zone, hit follow, then immediately hit S to break follow without actually moving forward much. Strafing > Moving back because backward movement is slow and strafe moves at run speed.

The only place I really use my group rotate (A,D) is when I've got a runner that goes by the group. Since you only have to get them within a 180° arc then the slight differences in facing aren't a big deal. Then once the alt is handled repeat the above, follow, then hit S and you're lined up for the next one you're tanking.