We have some similarities, being LH tweeners. I personally avoided this ball because I felt it too cover dominant for tweeners, not to say that it couldnt be thrown and have success. It seemed too strong in the friction and not enough in oil as you migrate in. Seemed to just be too over/under, hyroad cover, weaker core. Just my opinion. With that said, i would take to a pair of lanes and practice with the ball in the house you're struggling in and throw the ball at different surfaces you found one that you liked. Start at 4000, then 2000, and on down until you found one you liked.
The ball might also need a weight hole considering pin above and depending on how far the cg is out. The pin down equipment may be a longer pin to pap which is why you're getting more backend out them, whereas the pin up may be shorter getting the ball to flare more so it hooks sooner. Surface, however, would be the cheapest and better option.