"Can you use Phils wedges with the Murph's kit risers without changing the cables? How do they change the angle of the bars?"
The wedges only add approx. .300" in height under the outer-most of the three bolts in the stanchion base. This tilts the bars in toward the steering bearing making the bars more horizontal, and slightly shortens the spread of the bar-ends. This does not increase the span of the hoses, so, yes they can be used on TOP of risers. You may need a couple longer bolts though. On my bike, I re-routed the throttle cables from in front of the R. fork, to behind the fork and secure them with a cable-tie to the fork.
This photo shows the effect of the wedges on the handle-bars. The bar in the foreground is stock, the rear is sitting on the "wedge". Keep in mind the photo is on a flat surface but the top-clamp tilts toward the driver so the bars come very slightly closer.