However, I do not see (having read the e-book and Fyfe's general article on DU, and skimmed the FAQ) where he develops any calculus for the weighing of desires against each other that he bases the utilitarian part of the thesis on.
I've made the same complaint on his blog.
The best theory of morality I've ever found is the one invented by Alonzo Fyfe, which he chose to call "desire utilitarianism."
This short e-book (warning: pdf), written by a commenter on Alonzo's blog, describes the theory very well. He also wrote a FAQ.
One great advantage of this theory is that what it describes actually exists even if you prefer to use the word "morality" to mean something else. Even a community of paperclip maximizers may find something in it to be relevant, amazingly enough.