@ Zooker
At 500ft below the other aircraft wake turbulence would not be an issue. Wake turbulence sinks at a given rate behind an aircraft, so the 'following' aircraft couldn't lag too far behind without getting WT effect.
Vertical separation for wake turbulence is 1000ft, although I have had A321s complaining and asking for offsets when following below an A388 and being around 5 or 6 nm in trail.