i meant more ingeneral. i know the "chorus" of 12 bb is the last 4 bars.

i guess what i meant to post was what kind of changes shoulkd a chours be? i know there are no set rules for anything.

madhouse by anthrax uses a simple answer to the question, the verse is chords and the prechours/chours is riff.

its a hard couple of questions to ask i guess. with out writing a whole song right here and now.