Nobody has ever demonstrated that this makes any visible difference in the Panny plasmas. Even RGB input will look identical if the display is set up correctly. So its purely a theoretical question, and the Panny displays seem to handle color conversions correctly. It would be fairly easy to discern if they did not, and such an issue has not been reported.
In theory then, is there a best setting, not in terms of PQ (if indeed they are all the same), but in terms of least amount conversions being done? Also, should the Color Space on the Panny be Normal or Wide? Or does that depend on whether or not we send Deep Color (36 bit) from Oppo? Or are these items not related?
Several conversions HAVE TO HAPPEN between what comes off the disc and when the pixels light up. All you are doing by picking between the formats is changing whether the conversion is happening in the player or in some device downstream of the player.