I would prefer using Shaq to START, because he seems to be a beast when his tank is full those first 6 minutes.
Starting the fourth quarter with Shaq and Pierce would be nice, so they can get the C's into the penalty quick(er).
But it depends on the matchup. I can't see Shaq doing a better job than Perk on D12 or Bynum, but we will see soon enough.
I think with a few-possession lead late in the 4th, it's Perk's game to finish.
Either way, it's a good problem to have, and I highly doubt there will be any real chemistry issues. Shaq won't be offended if Perk gets the nod to start because he knew that going in. If Perk has to come off the bench, I assume he will understand it's for the betterment of the team.