Eddie :

Meadowlark's (ML) island is one of the best ideas I have encountered on the forum and is a great fish attractor and serves other purposes as he described. Think about what it will be used for and adjust ML's plan to meet your needs.

I would want it so the fish could use it for spawning on top as well so I would vary the top depth and put a hard surface on top like clay or small rock along with normal cover like trees or stumps or big rocks. For a number of reasons including geese, I would not add an above water island to a 5 acre pond.