Good clear concise best practice guide for GIT repo sizing and structure?

[Mark Montminy]

I'm looking for a concise "best practice" guide I can point project / repo owners to. While I can find many, I can't seem to find ones with the right balance of "why" without getting too deep into details, or being too thin, or sounding biased.

The problem I'm trying to address, is one I have to imagine other Bitbucket admins have run into, repos growing out of control.

It's my experience that users don't seem to understand the impact of large repos. When you mention the oft-referred to guideline of 1G they think that's nonsense, or just the admin's suggestion to save disk space.

You'd think insane push/pull times would be evidence enough, but the teams just complain about how slow the "system" is.

I'd like to share a guide with our teams that has an air of legitimacy to it that touches on the common sense "why" this is a good idea. Bonus points if it lays out straightforward solutions and remedies for those already in bloated repo realm. 

How do others educate users on this?