[Milhouse]

You shouldn't need anything in the config file to perform a basic re-caching operation on the local client, though it would take a long time to explain every setting - you'll need to review the thread (or changelog on github, which tries to mention each option as they're introduced and should give an idea of their purpose).

If you are missing artwork in the GUI, I would search Textures13.db for the url (ie. the path) of the missing artwork to see if the artwork has been successfully cached and is present in the Thumbnails folder. If the file is there, I really can't explain why it wouldn't be appearing in the GUI, if it's not there in the database or folder then you'll need to try and (force) cache it and check xbmc.log for errors which may explain why it's not being successfully cached.

Note that "lc" is to cache artwork for movies or tvshows added since the modification timestamp of the file specified as the "lastrunfile" property - it will have no effect on audio, you'll just process everything.