What is the best way to pull the boat over to practice righting?
If you're trying to work out how to perform a "controlled capsize" in order to practice righting, I'd recommend doing it under sail. Though it may sound violent, the H18 goes over very slowly... after about 30 degrees, the main almost seems to act as a parachute, slowing the capsize. You will need moderate wind to go over, though... sheet the main & jib hard, try to sail about 45 degrees apparent wind, and keep on the windward hull. When the boat starts to fly a hull, don't let out the sheets, just sit with your butt on the very edge of the hull. As it continues to come up, lean back so that you're actually sitting on the side of the hull. It comes up fast, but it goes over slow. Once on it's side, jump down into the water (off the keel side, don't go into the sail!)
Another advantage to capsizing under sail... it gives you a good idea of how far over the boat can go, and what it's like to capsize, so you can prevent it in the future.
Also note that, as John said, righting in little to no wind is actually more difficult than righting in moderate to heavy wind, and you may neglect one of the more important parts of righting, which is to turn the boat into (or about 45 degrees to) the wind. This allows you to use the wind to push on the trampoline, and help pick the main up out of the water. Practicing in no wind eliminates this aspect, for better or worse.
My wife and I have tried pulling it over using the trap wires alas with no success (combined weight of ~ 270lbs).
As was mentioned, be careful trying to pull the boat over that way, you don't want to end up under the mast, boom or main, or caught on the shroud when it comes over!
Also, ~270lbs is going to be too light to right an H18SX. I've tried and failed to right my standard H18 with 270 lbs combined weight. Make sure you have a third body available nearby to help right the boat when you try it the first time, or a nearby powerboat to give you a hand.