I'm sure about cutting the Hughes rockers - it tells you EXACTLY where they'll break. There are places in the engine where a sharp edge is a bad idea (piston dome) but harmless. Where that cut was taken is the worst possible place to remove any metal (the center of a span stressed in tension), and more so leaving a sharp negative profile with a violent change in cross-section.
If you absolutely have to remove metal there, cut only to the minimum depth to assure clearance (don't be surprised if some rockers need more than others - an extrusion or casting isn't accurate from the mold down to .001"), then blend & radius the cut into the parent shape in all directions so that the original cut is invisible. I would polish it, but that's just my OCD.