If I am driving stakes I used around 100 stakes. 10 to a row - 10 rows wide. It is hard to keep track of where you are driving the stakes so we use three anchors to control the boat.
If I am sinking condos I like to put at least 5 in one location. I like a H pattern. It gives you more edge for the fish to hide in.
Stake beds
x x x x x x
x x x x x x
x x x x x x
x x x x x x
PVC condos
x x
x
x x
Hope this helps.