I was looking at purchasing the LaRue Tactical Comp M2 Mount QD LT-150
but was wondering what advantages, if any, their LaRue Tactical Cantilever CompM2 LT-129 had over the standard mount.
I plan on running a magnifier also, and from I read here it appears that running the magnifier as close to the AP may be advantageous, at least it is with the T1.
The cantilever mount has a spare battery compartment. It also allows you to mount an aimpoint farther forward giving you more rail space for a magnifier.
The standard mounts put the magnifier closer to the Aimpoint (optic to optic), with the standard mount the magnifer has to be mounted one space to the rear on the receiver rail (as to where it is with the cantalever).
I found that with the standard mount it pushed the magnifer too far to the rear and I had to place my head in an unnatural position to get proper eye relief on the magnifier.
Due to this, I only used the magnifer on guns that I had a cantalever mount on.
If you want to use the L-129 with LT-649 pivot, you can switch it to the other side which will bring optic to optic closer. This is great for lefty also.