Kurt I personally don't think 45-50 degrees is too big a hip turn, unless you have a short backswing. No you don't want your left knee to turn in towards your right leg this tends to create swaying.Limiting hip turn to say 30 degrees makes you more of an arms and brute strength player which is basically how I play my punch shots but certainly not my normal shots.

Be interesting to hear what others have to say,

Brian

Your comment about keeping your left knee pointed outwards (straight ahead) is exactly right.You can make a massive hip turn and still maintain a knee flex, straightening of the right leg means you've lifted your body position