Friday evenings usually have low attendence in the first half of Haunt. Crowds can build up the last 2-3 Friday nights of Haunt. Keep in mind Friday evenings is just Haunt and whatever rides that are scheduled to be open. The kids's area, Planet Snoopy, is closed and no kid Halloween events happen on Fridays.
Just remember Haunt opens on a Saturday. Friday Haunt nights start the 2nd weekend.