We used to deploy our sixties like that years ago ;in a light role.When the Bns lost their mor platoons we started using the sixties with baseplate and bipod. guys will never fire enough rounds to get accurate trigger firing.A little trick we used was knotted string taped to the muzzle to swag elevation. and I didn't see if that tube had a sight line painted on it .
Yours didn't have the bubble sight on the trigger/handgrip mechanism?
As for ammunition required for effective employment, you could swag 3 rounds to get suppressive effects on a point target and maybe two at the most for an area target. So at the top side, 3x rds (say, M888 or M720 at 3.75 lbs if using current M224s) per tgt = 11.25 lbs. Do the math per engagement and the weight gets up there fast.
If the element is small, it needs access to a vehicle to stow it all. Remember this video?