The flapper normally has an air pocket used to lift the flapper but this will cause the second flapper to stay open. This can be solved by cutting out the rubber cone and by adding weight to the flapper. To fit the second lever you need to raise the lid about 3/8, so draw ten 1/2 x 3/4 rectangles in a acrylic sheet then cut them out. Now get the coat hanger and cut out the long straight piece from the bottom. In my case it was 1/8 so use a 1/8 drill bit to make a hole through the side of the acrylic pieces,be sure to use locking pliers . Once this is done use super glue to attach the acrylic pieces in pairs. You could also use waterproof epoxy.