Writing for 8 woodwind (and perhaps plus 2 horns)
Bass, 2nd bsn. 1st bsn will play, in order of preference: 8ve above bsn 2, unison with bsn 2, tenor part, melody octave lower (rare).
Melody, oboes. Flutes in unison or 8ve higher.
Inner parts, clarinets.
But it also can work thus: Sop: ob2, Alto: cl 1, Tenor: cl2, with fl 1, fl 2 and ob1 doubling these an octave higher.
In the 18c, horn parts were seldom melodically interesting; they thickened the inside texture, and the exact notes hardly mattered. More modern music is still influenced by this to a large extent, i.e. they are rarely melodic, so they often double existing inner harmony, maybe in a simplified form as they are not so agile as woodwind. 2nd horn can often take the bass if it is not quick-moving, releasing the bassoon for other work.
2 horns plus 2 bassoons is a stock substitute for 4 horns as they blend well
6) Balance. Remember that horns are a little louder than woodwind by nature, so two horns in unison is quite a strong sound. Oboes are no louder than other woodwind but their pungent tone means that they usually cut through the texture unless they are greatly outnumbered. Care with their notes, these tend to stand out. Give oboes plenty of rests anyway, for the sake of both the players and the audience.