If you do the same loop with tacky rubber and the same loop with non-tacky rubber and you try to feel the differences in effect and you try to create the same effect, if you have decent technique, the adjustments will come intuitively. The tacky rubber will always require more power or thicker impact and you will feel you are rotating the ball as you feel the ball stay longer on your racket. So you can hit into the ball more. The ball coming off will be slower, but it may have other compensating qualities like spin (relative to the power input) and control (again, relative to the power input). Other than how much you are hitting into the ball, the stroke will be essentially the same. This is what the coaches are talking about - a tensor rubber will have the ball fly off if you swing into it has hard. But some of this is really about harder sponge more than about tackiness per se. Because if you have power and you want to loop hard, there is a point at which your stroke goes to the wood (bottoming out) and you can't go beyond that and get good spin. So harder sponge (which allows for more compression with boosting, all other things being equal) lets you hit harder and still get spin, but the tradeoff is that you have to put in decent effort and good contact to get good spin and speed, which someone with a softer rubber may be able to do at lower swing speed. If you have an advanced stroke with good power, the tradeoff might be worth it. But it is one variable out of many. Some would argue that closing the racket works with a tensor, some would just say it is the softer tensors that have this problem, that harder sponged tensors do not. In any case, the mind body connection with equipment is a personal thing.
You are throwing the shoulder forward because you are not hitting the ball in your golden triangle. My point is that the degree to which you are turning your arm over the ball can be reduced by stepping forward or by folding your torso so you lean over the ball more so you are hitting the ball in the right zone. Use your torso lean and elbow angle to set the stroke plane. You can play the same stroke as you do but finish more forward without turning the arm as much. It will be more direct and more powerful because you will be hitting the ball closer to your golden triangle. The kind of pronation you are doing is usually a compensation for imperfect timing, not a bad thing under pressure in matches, but not how you want to practice without pressure when you know exactly where the ball is going.
The most important thing is to feel you are hitting the ball in your golden/power triangle. That way you are turning into the ball with your hips/body and getting good quality.
