I wouldn't advise placing the right index finger down the grip. It is actually creating some of your lack of control at the top. It gives your right hand a disporportionate amount of control of the swing when instead you want to have your hands working as one. It will often times lead to flipping the wrist prior to or at imact. Depending on where your weight is at impact it will lead to either weak slices or hooks; neither good. It will keep your left hand, arm and shoulder weak and get the swing started with the hands and not the lower body.
Maybe try placing your left hand in a normal grip with your right hand applying weak pressure and simply guiding. Try a couple practice swings holding off the left wrist through impact. That will help to visual the connection of the back of the left hand to the club face. The back of the left hand is in direct correlation to the club face. You'll notice that the left hand is always pointed at the target. When we're off, it's pointing at our misses.
Another thing to try would be to place your left hand with a normal grip and place your right hand in a four finger overlapping grip that again allows you to feel the pull from your left side, starting with your weight transfer from right to left leg. Make sure your left back hand is facing the target until just after impact and get your weight on your front leg.
I hope this helps. I think you'll be amazed at all the feel that it adds to the left side. I think that it can provide the confidence that we all need to get onto our left sides and not stay back. For most of us righties, our strong side is our right side. No matter how much we work to balance it, we will always favor the right just a bit. In practicing using a strong left side it will make the imbalance we have marginally less and that could be the difference of a couple strokes a round.