I can hit great backhands during practise but when it comes to the real thing it !@#$ up. My grip is a semi-western on the right and an extreme eastern backhand grip on the left. so i end up with a slightly closed racket face.
please help.......
First off, are you right or left-handed? If you are right-handed, why would you use such an unorthodox 2HBH setup? I've used something similar to your setup for kicks when self-feeding balls. It's good for hitting high and deep under the right conditions, but the timing, grip setup, and foot positioning is awkward. In a match or active rally, you're going to need to hit the ball well in-front of your body with that grip combination. This setup is not that forgiving on low-balls and you're probably hitting with a rather semi-open stance just to get the ball in.
You have to remember that your weak hand is the one doing 90% of the stroke. Because of that, there is no reason for your strong hand to be in the forehand grip. Your weak hand is in more-or-less a good grip for the 2HBH. Most people recommend you put your strong hand in the continental grip as you're strong hand is for stabilizing the backhand.
Setup in closed-stance, take back the racquet, move your hips and racquet together as you stroke low-to-high and finish your stroke with the racquet over your shoulder and touching your back. Meet the ball and make it a point to hit the ball with your arms extended and above the waist.
Hopefully that helps a bit.