A Tail Glow sweeper set could still probably work, as long as you bring it in on Special Attacks (Heatran's F-Blast, Milotic, Cresselia, Blissey). It could still probably take a physical hit or two, but it's better to be safe then risky.
And no, Synchronizers don't work on Cresselia or Mesprit.
Damn! I was hoping to reset for Ivs, but oh well.