The black smoke on sudden acceleration is normal, as you thought. The bluish white smoke is not typical of worn rings, it is usually just blue. Have you tried the oil-in-the-plughole trick? If it does not improve your compression substantially (so you can feel the difference when you pull the starter) it sounds more likely you have leaky valves. You might try checking the tappet clearance: if one or both valves has little or no clearance, it is very likely they are leaking. The whitish smoke is probably a better fit for leaky valves than for leaky rings.
