[Gippetto]

Reading all the replies and with my own experience, I feel the manual two person bleed is the best. With all due respect to Orrie 1& 2,, repeated pumping with no flow in the system will only collapse the bubbles momentarily and remain roughly as before. With vacuum and gravity bleeding the movement of fluid is so slow, bubbles can hang in high spots without being carried down stream. Pressure bleeding seems more effective if you provide a large enough reservoir to give a more continuos flow campaign.
Another though regarding pumping many times which may help the process which I saw using the vacuum bleeder. Repeated vacuum pumping caused the bubbles to break up and resize down to a froth like cloudy appearance. When the flluid stood for a while the air released from the surface and the fluid began to clear. I wonder if this phenomenon is what 100 pumps creates. If so, a hat tip to Orrie sr.
Is there a chemical engineer / physicist in the house?