Not a heavy metal driver or operated where wake turbulence avoidance was an issue but is not this analogous to flying an ILS "on glide slope". The wake of the previous aircraft will have descended below the glide slope thus giving you a smooth ride. From what I read, some following a heavier type, like to keep 1/2 to 1 dot high to avoid surprises. Wake avoidance material I read says at altitude, vortices sink at a rate of 300 to 500 feet per minute and stabilize about 500 to 900 feet below the flight level of the generating aircraft.
BOAC - I can recall some heavy 'wakes' following a sim.
