Here we go, unfortunately you are going to get several different opinions, but I will give my two cents. What you are describing, "tip stall" sounds more like breaking at the waist, in which there are several causes, mostly all form related. Have you videotaped yourself to see if anything stands out in your form? Breaking at the waist is a common probem on the off side as skiers cannot get their ski to react as well and wind up throwing the shoulders forward, reaching forward, etc at the last second to get weight on the front of the ski. This works, but when the ski establishes sudden angle, the skier is not in the position to handle it. I would suggest leading the turn with your center mass, never comprimising your hips. Focus on just that. If you are convinced it is the ski set up and not your form, make small adjustments to your ski until the problem diminishes. If its not your form and you can't get the ski to work, try a new one, maybe with a demo program.