From your website I see your in Georgia now... wish I was further
south... anyway I would consider the going deeper. I put in a pond
about the same size earlier this year with one 6ft x 3ft section 3ft
deep and I am going to redo it next year and get the whole thing 3 ft
deep at minimum. That way my fish will have plenty of room to swim
around and get big and strong. I will also hopefully get less temp.
variation. Hopefully your ground isn't too hard.