It's tricky art to make sure your weight is properly balanced. I have the same issue as you where I tend to come forward in the saddle a little. It's a habit I got from fixie riding. I saw a video where a guy gets in a trainer and no hands it with his hands behind his back leaning forward. That is where you want to be. Unfortunately for me, I do not have a trainer, so I am going back to the shop that fitted me and tweaking it there. Long torso, shorter inseam like yourself as well.