Ok, got it. Forget about the dial for orientation; a gunner can tell by minimap icon.
Change the elevation dial to represent distance, not just numbers, then mark the minimap also. Each grid and how many meters it represents.
To spot, the binocs will give a perspective as it does now. I say make it one from spotter's view. Simultaneously, the arty spiral warning you get for commander arty appears on the map once the gunner has that spot active. So all know to avoid that area. Also gives the gunner a sense of where on the map the spot is, so he needs only to adjust elevation based on his distance to target and orientation to it.
Switch target and the arty warning switches to that new target.
He can also fire at enemy spots ie the red enemy icons on the map.
Works for all arty imo. And allows gunners to fire in the dark, do basic calculations to represent more complex ones thus making them feel like badass arty crew if their aim is good. The arty warning also gives the gunner situational awareness to help him use descretion.