The US Army has things clear: from the hips. Except for the aiming problems.
To solve this problem, the US Army has created the "Enhanced Night Vision Goggle III" system (ENVG III), which is composed by a conventional night vision system attached to the helmet and a camera mounted on the rigle - also compatible with sniper rifles.
This camera is fixed to a set of optics and provides a 40º angle, the double of a conventional optic. The soldier aims through the visor that shows the images transmitted by the camera from the rifle point of view.