Thanks for the input. I have the same rocky issue, mine are a bit larger with a greater likelihood of large flat ones. Problem with the straight edge is the bucket will hit a rock about 3-4" in diameter in hard soil, then the bucket will want to walk up towards the surface, lifting the front wheels off the deck. It typically takes a few shots, articulating the bucket to get any bite to dislodge the rock, then naturally, there is another one 3 inches behind that...LOL.
It can get rather interesting on a grade with trees nearby, particularly on uneven ground.
Rock piles with various size rocksare also interesting, as they used an excavator hammer to remove a ledge where I am working, then they piled it. during the pile making, all the large flat rocks slid down the pile with each heaping, so they all typically lay against the bottom third of the pile, in layers, so you could imagine how it must be trying to get any bite with the BX. The pile is over 200 ton, and no I am not moving the whole thing, just need to build access areas in the excavated area and working the new driveway fill.
Nice job on the wall, good tie in's and overlap, looks like someone won't have a hillside to weed wack any longer....