I would have the pond be at least 4' deep. 10'x20' would be an ideal size. You could grow a large number of FHM for stocking your larger pond. As Ric Swaim said, keep all the spawning structure to one side so that seining it out will not be an issue. Feeding the fish will add to the numbers. FHM are very low DO and poor water quality tolerant so there is less worry with issues with them. FHM are only good feed for bass up to about 12"-14" IMO. Once your bass get over than size, they are going to need something more substantial to feed on... FHM only reach 3" or so in size. You may want to consider raising GSH as they get to a much larger size.