I think the “two threads” idea has made a promising start, even though we should not hope for perfection, as we were warned when the idea was mooted. There’s an answer on the other thread, snd some unexpected caginess on this one.
Isn’t it strange that we are told to remove the extra words before solving, and yet by the time we get that instruction we have probably solved the clues already? We may or may not have spotted the extra words, of course. I didn’t spot the extra word in 11d, whereas I thought the word “surface” in 31a was an extra word.
I found the puzzle ingenious and educational, as I had never heard of the author or of his whimsical approach to writing a book!