To make three cakes, you will need 6-, 10-, and 12-inch springform pans.
Prepare charlotte molds: Line 6-inch, 10-inch, and 12-inch springform pans with parchment paper. The paper should extend an inch above the rim of the pan. Spray parchment with cooking spray. For the 6-inch pan, trim the bottoms of approximately 15 ladyfingers and place, rounded sides facing outward, in the pan or cake ring. Trim the 5-inch biscuit-base piece to fit snugly inside the ring of ladyfingers. Proceed with the same technique for remaining charlottes, using approximately 26 pieces for the 10-inch pan and approximately 34 for the 12-inch pan.
Pour Bavarian cream into each pan as follows: 10 cups of cream for the 12-inch mold; 7 1/2 cups of cream for the 10-inch mold, and 3 cups of cream for the 6-inch mold.
Refrigerate at least 8 hours, until firm enough to release springform mold. To serve, top each cake with assorted berries; about 9 cups for the 12-inch cake; about 6 cups for the 10-inch cake; and about 2 cups for the 6-inch cake.