I rigged a kite on a P-19 a few years ago, and on a Nacra 5.5u a few years before that. Your gear sounds fine; I started with a kit from (then) Sailing Pro Shop that included a 12' carbon pole, sheets, halyard, and blocks. Prebend? Always. When you pick up the front of the boat by the tip of the pole, the pole should not go straight, let alone invert. As for height of pole tip, remember the lower you pull it, the greater the side loads on your hulls. I used a really long pole on the 19 (I had a big kite) and never had the lines break or pull out.
Good luck