When we were on the Century for my bd in March, we bought a wine package which included 2 nites of Opus One and the rest Dom P. The money we saved more or less equated to the gratuity. We thought we did ok as other cruise lines did not have this type of package, which allowed us to spend more on other things.
Cheers, a votre sante, bottoms up, down the hatch,
and Happy Cruising!