"Anonymous" is asking questions about the mass of the d-quark tangle. I am not the right person to discuss the problem, but I'll try. I recall that when I first read about tangles defining mass, I was confused. Schiller does not explain the issue very well; but he says that more complex tangles have higher mass and rotate more slowly.
Somewhere else he writes that there is a problem with the down quark: the spaghetti model predicts a smaller mass than the up quark, because the down quark is simpler. A simpler tangle has a smaller mass. What does symmetry have for an effect? I don't know; "Anonymous" writes that it should ease rotation. Then symmetry reduces the mass and makes the problem worse. And now?
And what is the difference between an up and down tangle anyway? The tangles (page 287) seem the same to me.