North Carolina’s wildlife agency identifies small Clouser-style flies with flash as a useful shad choice. Florida’s agency likewise notes that American shad strike small bright flies. Carry compact patterns in a few visible colours and, more usefully, a few weights. A lightly weighted fly and a heavier one answer different questions in the same current.
Make the first casts short, then lengthen them gradually. An upstream or across-and-upstream cast gives the fly time to descend before crossing the likely lane. Allow it to travel under control, taking up excess slack without hauling it immediately back to the surface. When the fly has swung below you, give the hang a moment before retrieving.
Count down consistently so the next cast can reproduce the depth. If you touch bottom on every pass, shorten the wait or lighten the fly. If the presentation races over the target, change the casting angle or line control before deciding the colour is wrong. The aim is a fly travelling near the fish, without dragging a hook blindly through them.