Fred, OS recommends their #8 plug. I've had really good luck with them. Have you given that a try? For the adjusting, sounds like you may be trying to squeeze a bit too much out of the engine. When I point the nose of the plane up I expect the engine to actually speed up a bit at first, and then stay there. In the past (long time ago when I was young and foolish) I found that if the engine did not speed up a little when I pointed the nose up, it would lean out in flight.