pikey, go with the Big Berthas or the X-22’s. These are high playability irons and they will definetly help you. There is no such thing as having too much playability in a set oif irons and they will not hurt you as you improve. They will actually make you improve faster.
I am not a big fan of the Uniflex shaft but it will be fine for you for some time. When you get down to somewhere around a 14 handicap or so, you simply need to have your swing speed and a few other things evaluated to see if a shaft change is in order. I like the #4-PW for your handicap allowing you to fit in at least 1 hybrid and possibly 2 depending on your fairway metal clubs (distance wise).