I have two sets of older Mizuno blades (MP-32 and MP-69) currently with TT S300 shafts.  These shafts are a little too heavy and too stiff for this 66-year old body of mine.  I really like the feel of these irons and would like to replace the shafts with something lighter, less stiff, and more energetic than the TT S300.  Maybe something along the lines of the TT XP100 shafts that came with a set of Titleist AP1’s, which I like a lot?  (Also, I want to avoid graphite shafts, based on my experience with a set of MP-32’s with older Fujikura Vista Pro shafts–the  graphite seems to affect the feel too much of the soft, forged Mizuno heads, which is the main reason for playing these irons in my opinion).  Any suggestions would be greatly appreciated.  Thanks.