FishingRod,
That is a lot of questions! I can't possibly answer them all but I think would like to address a few.
For any forage pond I think the ability to drain is very important and when you can use it seasonally as opposed to year round it allows for drying the basin which will mitigate vegetation issues and insect predators.
I do know that for production/area that smaller is better for Gams which like edge. Also filling with brush like cedar greatly enhance production by providing substantially increased surface attachment area. The brush applies to everything to include any other minnow species, crawfish, and also BG and other lepomis. It would also help TP. You have to remove brush to seine so if you can devise some system that works for you then that would be a way to get more out of a small water body.
Gams don't need fish fry as forage. They will prey on their own young but this usually is not a problem when sufficient other zooplankton forage is available.
The very best thing you can do for small fish is fertilization by organics in a pond that is freshly filled. Zooplankton can eat it directly and as it decays it will release nutrients for phytoplankton creating a smoother bloom sequence and better water quality than bloom created by inorganics (which blooms can get away from you more easily). Rice bran, cottonseed meal, and alfalfa are all good for this type of fertilization.
