i wish people would give their age and stats, including a brief cycle history when asking cycle question... i know, that's not what you're asking about, it's just a little peeve of mine.
personally i think dbol is best used for relatively smaller lengths of time, like 2 weeks at a time.
if you use dbol for that long, however, i would strongly suggest using something to protect your liver; especially alpha lipoic acid. ...and plenty of it. i prefer to use r-ala.
also, i don't think 30mg is even necessary with dbol, 20mg spread out evenly during the day will get the job done quite well.