I like to run my AT Pro in "All Metal"
And yep I've tried a lot of settings. For me this works. I live in an area where the average GB is in the low 90's high 80's if I'm lucky. And lots of hot rocks.
I run Pro Zero , Zero disc & Iron audio ON...Yes iron audio on.
That makes everything respond with either low or high tone with a much cleaner target separation. What I'm looking for is small solid targets.
When I find a target I can usually tell if its a small coin or multiple targets what have you. You also have to watch the VDI & hover over any solid that rings at 40+. Typically a solid target will rise in VDI when concentrated over. A foil or corroding target will drop.
That's my secret setting-Might work for you might not. But I'd wager its deeper & much better in trash.