I just got a set of Rome Targas on a 4-5 year old all mountain board. I had the tech at the shop mount the bindings. Normal width, centered on the board. However, that's not the end of it. You need to get the boots in the binding and make sure they are centered on the board. If not, then you need to perform a heelcup/highback adjustment. You also need to adjust the ankle and toe straps to ensure they are centered on the boot when they are cranked. In addition, in order to dial in that heelside responsiveness, resposition the highbacks so that they are parallel to the width of the board. I'm willing to bet that is the problem regarding your heelside turns.
The tech at the shop did none of these adjustments. I had to come home with the board and make all of these adjustments with the boots in my hand.