Question: Which grip combination should I use for my two-handed backhand?
Answer: The most common grip combination places your right hand in a Continental position and your left in an Eastern forehand position. This grip is stronger for most players than having both hands in an Eastern forehand position. Some heavy topspin hitters move the right hand close to an Eastern backhand position and the left to a Semi-Western forehand position, but this grip requires a point of contact farther forward than the others, and it has more trouble with low balls.
See much more here: Photo Tour of the Two-Handed Backhand Grips