[BenG]

The biggest benefit to weapon mounting NV (and the only reason to me) is that you can go prone without having to crane your neck at an odd angle. however if you dont spend 90% of the night on your gut and you have a decent gen 2 device or better I think you will find yourself wanting of a helmet mount, its just to much of advantage to not be looking through the NOD all the time.

If your really set on weapon mounting, which it seems like your fairly flexible consider getting I think it was the aimpoint QD mount it breaks into 2 peices one stays on the rifle the other on the nod, and you can have a j-arm attatched at the same time so you can quickly transition from head to weapon mount in a pinch.