Like some other posters here I found this one a bit of a trial. I thought the preamble was a bit too vague to be much help, and as has been already noted, there are a couple of exceptions to the cryptic directions in the quotation. (It did not help me that I hadn't previously heard of the person being quoted, and that I don't have a copy of the ODQ and had to rely on picking the 'right' translation on Internet!)
That said, I spotted some of the thematic changes fairly early on - the undead cow and the sponsors providing the breakthrough. Delighted to see quite a few Scottish references in this puzzle too.