When you speak of "2 X 4 exercises" I am guessing you are referring to the so-called "2 X 4 forward stroke technique", a moniker coined by Andrew Westwood?
http://westwoodoutdoors.ca/2010/02/24/c ... -westwood/If so, I feel compelled to mention that Andrew hardly developed this technique. People like Tom Foster and Charlie Wilson had been talking about inside circle carving for many years prior.
As for DVDs I agree that "Drill Time" is quite good. An older, but still good Kent Ford video is "Solo Playboating":
http://www.performancevideo.com/solo_playboatingPerhaps my favorite DVD is Tom Foster's "Solo Open Whitewater Canoeing":
http://whitewatervideo.com/TomFoster.htmTom really emphasizes the value of circle carving in his videos, just as he does, or did, with his face to face instruction. His emphasis has long been on the "cab forward" technique of driving the boat from the forward quadrants.
There are many fine books on whitewater canoeing. A couple of nice ones that cover whitewater canoeing as well as general canoeing are Andrew Westwood's "Canoeing: The Essential Skills and Safety" and Gary and Hoanie McGuffin's "Paddle Your Own Canoe: An Illustrated Guide to the Art of Canoeing".
As for flat water exercises I would suggest making a couple of small buoys. Using a single buoy, practice paddling in circles of varying radius by carving on both your on and off sides, touching your bow to the buoy each time. Using a pair of buoys, practice paddling a figure of eight pattern around the buoys by carving circles, switching from and on side to an off side circle, or vice versa, at the midpoint of each figure eight. These are exercises Tom Foster suggested to me years ago, and I was a little amused to see them recommended in the McGuffins' book as well.
If you don't have a lot of solo whitewater canoeing experience you should be aware that the Nova Craft Ocoee is not the most user-friendly boat to start out in. The Ocoee is a great boat, but the original Dagger Ocoee has a significant edge to it. As you have found out, the edge or chine can be used to great effect to maintain directional stability on a ferry, or maintain a carving arc by weighting the appropriate knee. When you start to paddle a sharper-chined boat on whitewater you will likely find yourself tripping over that chine if it contacts an unforseen rock, however. Eventually you will develop the ability to instantly and instinctively unweight the downstream knee as you make contact with such a rock but expect to take at least a few swims first.
The Nova Craft Ocoee mold was taken off an Ocoee that had been pulled in two inches or more for slalom racing. This rounded the bottom of the hull significantly and made the boat less stable (but faster). If you find the Nova Ocoee too tender for your taste, you might be able to improve stability by pushing it out a couple of inches by either relocating the thwarts or installing longer ones.