it really doesnt matter. its already been stated, it depends on the writer. if everyone followed the same line to bar ratio then you would have a bunch of chumps that sound alike, (ex. 90% of rappers on the radio 2chains, waka, gucci, jucie mane, soulja boy, etc...) all of them sound alike and pretty much have the same scheme "rhyme this word with that word and call it music"
i personally like to rap fast so i can fit more shit into a line, where some who rap slower dont put as much in their lines. it all has to do with your style, your content, your vocabulary, and all around skill.
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