Never fished for Hickory shad, but drawing from Scott's suggestions, looks like they take the same flies as American shad, which are still fairly common out here. I do not have any photos of my own patterns, but in my area basic shad patterns are bead chain or dumbell eyes, and something bright on a #6-8 nickel-plated hook (e.g. Eagle Claw 1197N). A local favorite is the "Wet Pinky". Another you might try is the "Bowstring" which is has bead chain eyes, short tail (marabou or globug yarn), Amnesia abdomen, and chenille head. Here's a commercial western tier's list of patterns which might be helpful.

One trick that has become more common on our rivers, and may well work in yours as well, is to use smaller flies as droppers. They are quite often the most productive fly of the day. I for example put glass beads on a scud hook (5 green, one black as the head) and secure with monofilament thread, to make a quick and dirty caddis pattern that works quite well in our tailwaters. Might not work in a tidal estuary, if you can find some smaller hooks, try a few micro patterns (#12-10) as a dropper and see if it works out there too. Best of luck.