Just to clarify where you stand on norms: Would you say a person is obligated by facts woven into the universe to believe that 68 + 57 = 125 ? (ie, are we obligated in this sense to believe anything?)

To stick my own neck out: I am a realist about values. I think there are facts about what we ought to believe and do. I think you have to be, to capture mathematical facts. This step taken, there's no further commitment required to get ethical facts. Obviously, though, there are epistemic issues associated with the latter which are not associated with the former.

Morality as the expression of pluralistic value sets (and the hypothetical imperatives which go along with them) is a very neat explanation of the pattern we see of agreement, disagreement, and partially successful deliberation.

Would it be fair to extrapolate this, and say that individual variation in value sets provides a good explanation of the pattern we see of agreement and disagreement between individuals as regards moral values - and possibly in quite different domains as well (politics, aesthetics, gardening)?

You seem to be suggesting meta-ethics aims merely to give a discriptively adequate characterisation of ethical discourse. If so, would you at least grant that many see (roughly) as its goal to give a general characterisation of moral rightness, that we all ought to strive for it?