RE: Nose dive
Easy part first. A great second plane is the 4 Star 40 or 60, Tiger 60 or better yet for the winds would be a pattern style plane ( Javelin II, Tower Hobbies Kaos and the like).
If the plane is diving, the last thing to do is stick weight in the nose. I fly the Power Point and have yet to see that effect. Something else is going on.