You def DO NOT want to transfer between terminals just for the Centurion Lounge. With the airport construction the ride could take a while to go from B to C/D.

The new SkyClub in C is smaller and I seem to recall it didn't have the full usual spread, but it was a while ago so things could have changed. I would just stick with the main club in C unless it's totally packed which can happen in bad weather. I've been in the main C club when it's basically been standing room only.