I just went through this myself. I searched all the internet recommendations and came across many. My current iron shaft is the Nippon 950 Neo in stiff. I'm right between a R and a S but since it's a lightweight shaft, the S works out. I tried the heavier route with the KBS Hi-Rev 2.0 in my 54 and 58 and same shaft in P and G. Then I reshafted it to the Nippon Wedge 105 which is Nippon's wedge specific shaft, just like the Hi-Rev is KBS's. All were fine, no complaints. Then I read more stuff and tried same irons shafts in a softer flex or soft stepped. So now I have the Nippon NEO in R in my 54 and 58 and so far it's my favorite.