I know what you mean about problem sets. I taught for a couple of semesters and I hated writing test problems. Even after checking my work, I would sometimes miss things. Like finding a typo in a problem statement
AFTER I had printed 50 copies of the test. There would always seem to be some little thing like that. The worst was if I was in a hurry (or just careless) and didn't double check my math. There's nothing more embarrassing than making a simple math mistake and getting caught by your students
. But I tried to keep a good sense of humor about that kind of thing, and the students were pretty understanding.
Your book sounds like quite an undertaking! I do love a good reference book. Right now my big book of engineering goodies is the 'ME Reference Manual' (one of those all-encompassing study books for the PE licensure test). And then I have a small collection of other books for when I need to get more specific.