I have found that just a hook and freash bait will work just fine but I do keep a stash of fluke rigs like the ones you have made up. This time of year in the tidewater Va area the bigger flounder are in deeper holes from around 45 to 80 feet of water. Check out this link of a guy who caught a 12lb 12oz 31inch flounder this past weekend from one of this fishing holes. I have never hooked up on any fluke of this size but its nice to see that there are some around that size which gives me hope of landing the big one.
http://www.tidalfish.com/forums/virg...ig-flatty.html
Hope the link works. To catch these big fish guys use live spot or croaker around 5 to 6 inches long. You have to scroll down to about the middle of the page to see the pic.