I think I know what Steve R's answer would be! 
While I usually play players as opposed to post positions, there have been times where the quinella combos I really liked have been bet way down, and I've instead looked for value by turning to combos with the 1 or the 2 (like 1/567 or 2/567), whichever was paying more as a group. I've hit some pretty nice quinellas that way.
