Well Dan, I tried cooking Hard Heads once and it didn't go so well. You cut off the heads and tails, gut them and then soak in salted water for 24 hours and it came out kind of bland. Gafftopsails are a different matter, they're a large fish that you can fillet and broil or grill. Pretty good.
When I occasionally indulge I get farm-raised catfish from the grocery and sometimes do them Cajun style. Mighty fine.