(2016-02-17, 7:13 pm)zx573 Wrote: Have you checked どんな時どう使う 日本語表現文型辞典? I don't know sure what nuances are listed at the bottom of the description in Kanzen Master N1 so I can't say for sure if it's what you're looking for, but it has a lot of N1 grammar (and everything before) but it's been pretty good in my experience for everything I've looked up. べく and んがため（に） are both in there, too.
Does it go into detail on why you would use one over the other?