I hear
boustrophedon either as two unaccented syllables, though with the first slightly more stressed than the second, followed by an accented and an unaccented syllable; or alternatively, simply as two trochees, thus
boustro
phedon. An example of the
first and of the second
second. The received pronunciation in English allows at least that much variability, so I would stress whichever way accommodates the meter at hand in the context. If that helps any.