I don't fish Aransas, but a flounder is a flounder, right? My preferred flounder fishing is done on a falling tide in marsh drains where there is moderate current pushing bait. Something light in weight that will move a bit with the water flow when it's hopped on the bottom. A sixteenth or eighth ounce head is plenty, depending on current. You might have to try more than one drain but when you find the right one they'll be stacked in there. The larger ones are most likely to be found on the outer edges where the current may eddy a bit, out of the main push of current, and even a bit farther out from the drain. Fish slow and don't be impatient with the hook set. When you feel that thump just tighten up the line a little and feel things out........you'll know when to hit him. Flounder are not afraid of a bait with some tension on it and are famous for hanging on all the way to the boat before letting go. Gulp is good, as is any plastic of moderate size. A good gel attractant smeared on there will often make them hold it longer if it's not Gulp. Generally dark colors since it's bottom bouncing but that will vary with water clarity.
Knowin' where you're going' is mostly known' where you have been.