Meta-pull request -- how should I structure pull request(s) for these changes?

This is a set of changes we are or will shortly be using at Palantir.  I'm not expecting you to accept this pull request as-is (the RFC patch is clearly wrong and breaks the tests), I'm more looking for what you'd like to see.  Some particular questions I have: Should I break this pull request into multiple separate ones with logically separate changes (e.g. restricting emails by regex to a subset of refs (a combination of 138837c and 8b12ebc), emitting single pushed commit as a single email, new GerritEnvironment, new StashEnvironment, Atlassian Stash plugin)?  Should I keep one big pull request but reorder a bit more to group adjacent commits into the same category?  Does it make sense to include this Atlassian Stash plugin that wraps git-multimail in this same repo or should I just put that stuff in its own separate repository?  Should I quit being lazy and add some tests to t/test-email-content?