I'm curious, did others find Chapter 45 as deeply moving as I did?

It would seem so !.

I'm not sure if I'm alone but I've been moved previously by other writings by Eliezer and others and it's like I've, well, been moved. Death is taken for granted a known enemy to be killed on sight. Putting myself in Harry's shoes the reaction I experience is "Death. F@#$ that! \<implacable motivation\> Whooosh!"

The other difference I suspect I would have is that I wouldn't expect to have a human patronus. I would expect something like sentient (white) fire elemental or an elf (symbolic of an intelligent creature with humanlike values, not precisely human and the better for the difference). Perhaps I'm not a humanist so much as an intelligent-life-with-my-values-without-the-outright-obnoxious-parts-of-humanity-ist.

I'm was having trouble avoiding crying when Harry tells the Dementor why death shall lose.

That part I shied away from. It wasn't arational emotion; it was irrational. Being passionate about life with a proactive, vigourous intent to see it flourish doesn't mean you must mangle your beliefs such that you are overconfident. "Death shall lose" is a false claim when the correct belief is "there is a certain chance that death shall lose and it is all the greater for my efforts!" "Death shall lose" is just denial. I wouldn't be able to create a patronus powered by denial because I've trained myself to see denial as the brain's way to make pessimism palatable.