Kind of a late reply...having been out of touch for a couple years. We have sailed Sports quite a bit over the last ten years. They are certainly stable, under sail, and we have learned to use the "sailing" as a mileage stretcher on big waters. A couple of tips, from our experience:
1. Carry some additional small bungee cords (shock cords) that do not have sharp metal hooks. When the wind gets too big, its nice to drop the rig in the water, roll the sail, tie it up, and put the sail into a paddle holder until you can get to shore or a calmer bay/inlet. You should use additional lines to keep the sail from coming loose while doing this trick, and dont let to much stick out ahead of the boat or you will stick it into waves. As soon as safe, get the sail off, folded and stowed, and the mast back into the paddle holder. When it is going to be a big, wet, and "ugly into waves" to get home, pull the mast apart, wind the shock cords on tightly, and restow on the side.
2. ALWAYS tape the two-piece mast together with black electrical tape before you head out. You do not want the mast to separate while your are busy derigging in the middle of big water. Also, pay strict attention to the batten retaining line....I use a figure eight knot on the end of the tie offs, and a piece of duct tape on really bad days.
3. We also have a 60" piece of black, Schedule 40, 2.5" ABS plastic pipe. Using flat tie down straps, over the tube, fed down through the rear drain holes, out to the sides, up over the pipe, then back under and up through the hole (repeated on both sides of the kayak with one strap, tensioned in the middle with a shock cord over the pipe)....we connect two Sports as one very stable catamaran. The flat straps are against the bottom/sides of the hull, from the holes outward and up the sides...so there is a little extra drag. We arent going all the fast, anyway. This arrangement lets one person pedal and steer, alternating, or both together, or both sails can be used, or just one. Downwind speed is pretty impressive this way. For some reason, the "catamaran" seems to surf pretty easily off of boat wakes when running under both sails.
The flat gunnels across the back of the Sports are really great for "catamaran" kayaking, and the added stability will really save your overall energy when you get a long way out in the middle of something like Flaming Gorge Reservoir (only a little over 100 miles long, after all). We've used this often, without sails, because it is so relaxing and comfortable and makes for great picnicing on the water!