Stops sit beyond the structural edge that should hold if your thesis is correct. For VA edge rotation: beyond the VA edge being rejected. For nPOC: behind the naked POC level.
Give a small buffer beyond the structural level — not at the exact edge everyone sees. The point is not to avoid every sweep; it is to define invalidation where the thesis stops making sense.
Avoid obvious round numbers as stop locations. If your stop is at a round number by coincidence, that's fine — but don't place it there because it's round.