Wedding cake portions traditionally are smaller than usual dessert portions because they are most often served after a large dinner that includes other desserts. Some servers cut thin slices from the full height of each sandwiched tier, 4 inches high by 2 inches deep by ½ inches wide, but you can also cut a square 2 inches high by 2 inches deep by 1 ⅝ inches wide.
The most practical way to cut 8-inch or larger tiers of wedding cake is in concentric circles until the small 4- to 6-inch center round remains. This section can then be cut into narrow wedges.