To get a specific number for code coverage, I would need sometime to go through all test file and find where the work can be done.
I can share with you a draft on what areas I will cover in user docs along with a prototype of how the things will be arranged in it.
Also bookbrainz uses readthedocs to host the docmentations while musicbrainz shows them on the website itself. Should we go ahead with the our current template or should we also make all the documentation available on the website.
I will get back to you a proposal covering the points you mentioned along with the user prototype.