Sharing FCPX Proxy Files

I have a 250gb FCPX Library that I want to share with my editor. But the library is far too large to share to dropbox reliably. SO I want to share just the proxy files with them so their workflow can be smoother and my upload can be faster.

Has anybody figured out a way they can do this effectively? Since everything is contained inside the FCPX library, I'm not quite sure how to do this without breaking anything. I have a few theories but want to hear from somebody that has actually done this. Thoughts?