I am pretty sure there isn't a tutorial that meets all your requirements. Check out Jaxov's post for a start.
Anyway, Greasemonkey's not that hard once you know JavaScript; even though Greasemonkey on Chrome can be a bit of a pain.
Play around with it; examine code that works. You could be the one to write the updated "Getting Started" documentation ;)
Also for Chrome, check out Tampermonkey.