Hi, you should also consider the tag mapping used by Picard (the Musicbrainz tagger), although Picard isnt as popular as some taggers files tagged with this tagger are tagged comprehensively due to the data-richness of the Musicbrainz database.
In particular note Picard already uses:
COMPOSER TRACKTOTAL DISCNUMBER DISCTOTAL
ENCODEDBY not ENCODED-BY BARCODE not PRODUCTNUMBER
Ijabz 9 November 2009