I have two suggestions. Include more information on the web site and include what was selected for compile in the completed email.
Include more information on the web site
Ok, like what? What were you missing?
include what was selected for compile in the completed email
Yes, definitely. I realized that many users commission several builds in quick succession and then won't have much clue as to what a particular binary contains when they get several success emails in quick succession.
For a moment I thought about letting users give their builds meaningful names but I believe just stating branch and selected modules in the success email is enough. Furthermore, the firmware filename should be something like '<branch>-<number-of-modules>-modules-[integer|float]-<hash>.bin' or so.