Free jump colliers keep your hands in the best position! It teaches you balance and trains your hands to hold the reins properly for when you don't use it
Leg is the answer to all problems.
When you are riding, just be aware of what you are doing, don't subconciously pull on the inside rein. Inside leg with outside rein are a golden combination when getting a horse to relax and be soft.
Stop working on getting the horse on the bit, and start working on getting the horse to move from its hind end, and picking it's back up. Hands are passive.
When you are getting your horse round you should use A LOT of inside leg and outside rein. So this is something you should be really aware of doing! If your horse is still pulling down, never pull back! (They are stronger than you) when they are pulling down they are putting their weight on that rein, by pulling back you are supporting that weight. You can give them a little scare by dropping that rein. This way they will realize you will not carry their weight and they can not support their weight on the reins