Wedge Shaft question!!
My personal opinion is that you don't get spin from a shaft alone.
This is more how you hit the ball.
A shaft can contribute to that ok, but a shaft that makes you spin the ball??
I think you should check what is in your irons at the moment. And try matching them
to get the same feeling. I use the KBS Tour stiff shaft in irons and wedges. I do get a decent amount off backspin.
You might consider Cleveland wedges. The last several years of the CG wedge line featured the TRAction (Tip Responsive Action) wedge flex shaft as stock shaft. The TRAction shaft had a more flexible tip for better feel, and a stiffer butt section to promote a lower launch.
This was a variation on the Dynamic Gold S300 shaft.
I cannot tell from the Cleveland promo material if the TRAction shaft is still standard for the 588 Forged (2012) and the two new 588 RTX models.
Personally, I don't enjoy the DG except for the Spinners, in a wedge. A shaft without much kick, as DGs are, imho, are not the best for your 54-60 wedges.
Now for the PW and Gap, I'd say if you don't use them around the greens, just go with your iron shaft.
I've had KBS Hi Rev and the Spinners - I've had good results in the higher lofted wedges with the Hi Rev, and they come in different flexes.