The pond build in 56 is two acres, the one I'm bringing up a new generation of crappie in is 4.
Enough of the "Old School" thinking, The only downside of Black Crappie in a small pond is that they compete with other predators for forage. HSB are more than capable of controlling Crappie. Ponds stocked with bass/bgill several years prior to Crappie work too. Water needs good visibility.
With the addition of tilapia, a healthy forage base should keep up the predators RW's too.