These are very interesting thoughts Jerry!  I'd like to raise two or three questions about them.
In your first post, you write that there cannot be (objective, non-person-dependent) grounds for claiming either that A > B or A < B, and no grounds for denying that A = B.  But it seems to me then that, equally, there are no grounds for denying A > B or A < B, and no grounds for claiming that A = B.  Aren't the self-restricted interests of A and B simply incomparable or incommensurable?

In your second post, you write that we can invent values with objective validity (by which I think you might mean, given the context of your first post, interpersonally or intersubjectively valid).  But why does it follow that, given that there is no basis for regarding one subjective sphere of normativity as more important than any other, that they must be equally important?  

It seems to me that, if we have to attach preexisting labels to your position, it would be constructivist, and more specifically contractarian.  (My apologies if I have misconstrued your position.)  It seems to me that the procedure for inventing, or arriving at the "unlimited, objective" values from limited, subjective bases would involve either hypothetical or actual agreement, based on mutually acceptable reasons.  But if this is so, what reasons would prevent the stronger parties from imposing unequal terms on the weaker parties, biased in favor of their own interests?  How would you convince the strong to treat the interests of the weak on equal terms as their own?  I would like to know.

Thanks for reading.