Definitely "incomparable" fails to imply "equivalent". But still, where two options are incomparable according to your morality you can't use your morality to make the decision. You'll have to decide on some other basis, or (possibly?) no basis at all. To my mind this seems like an important fact about your morality, which the sentence "my moral preference between A and B is that they're incomparable" captures nicely.

Good point. Let's try something else then, vaguely related to my first idea.

Suppose you are given lots of time and information and arguments to ponder, and either you would eventually come up with some resolution, or you still wouldn't. In the former case, I think we've found your Actual Moral Judgment (AMJ). In the latter, I'm inclined to say that your AMJ is that the options are morally incomparable: neither is better nor worse than the other.

Of course, this analysis doesn't help *you* make the decision. It just gives an impartial observer a possible way to understand what you're doing.

Lormand has a better take than Dennett. Dennett thinks qualia would have to be irreducible. Lormand writes

If such arguments were convincing, they would weigh against any reductive theory of qualia. But they should not be convincing. A powerful but not dismissive response turns on distinguishing qualia properties from ways of representing them. Even if a creature has a special way of representing phenomenal properties that is unavailable to us, we can in principle objectively specify, express, or test for these phenomenal properties in other ways.

Dennett simply defines qualia overly narrowly, letting the least naturalistic philosophers own the term.