Be sure of your goals !!! What do all the owners want? I will point out to you the main difference between a large lake and a small pond. One is like a train the other like a bike. You can manage/change a small pond like stopping and turning a bike. With a large lake it is like a train - you don't change things easily/fast once its in motion.

Also a large water can make use of pelagic (open water) fish species better. Bob Lusk has managed large lakes of many types all over the US. A short call to him is well worth your time before you start the train rolling.