Where should a sporting rifle (DGR in this case) balance point be?

Antlers,

I believe it is generally thought to be at the front guard screw.

Malm

Antlers---

The rule of thumb is 50% of the gun's weight should be between the hands.

If you shift weight to the rear it speeds the handling and towards the front is slower and steadier.

I like the center of gravity in the center of the front crossbolt if it has as scope and middle of the magazine box for iron sights......unless it's long range iron sights, then move it way forward.