I think I disagree. Mine with bad rings smoked most under high vac. like on decel in gear from speed, but it smoked all the time. My leaking valve stem seals smoke most after prolonged idleing.

Bad rings will smell like burnt oil. Bad exhaust valve seals will smell like vaporized oil, like an oil spill on a hot exhaust manifold, since the oil doesn't enter the combustion chamber.

Under heavy accel, you won't see much smoke from leaking valve seals since the exhaust back pressure pushes against the leak. Alternating pressure pulses in the exhaust under idleing seems to pull the oil into the exhaust stream.