Driver fitting

I have slowly worked my way throught the bag getting fitted for Titleist. First I was fitted for 3 Vokey wedges and saw some short game improvements that got me down to bogie golf. Then I was fitted for new irons (AP 1's in the 712's) that brought me from an 18 handcap to a 15. And recently I replaced a few of my long irons with a couple 913 Hybrids in 24* & 19*. Now my handicap is 13.3. Naturally I'm considering a Driver. Due to some shoulder issues my swing path is a little steeper than it should be and I have to much back spin. Its better than it was thanks to a good physical therapist. I was generating 6000 rpm's with my driver. They were laser straight, but very short. I've been able to flatten out the swing a bit, but still have more spin than I want. A buddy let me use his 913 D2 this weekend at the range and played with the setting and I was very impressed. He said the D3 is a little smaller head and has less spin. Can anyone explain the driver shafts and how they reduce spin? My goal is to be able to clam a single digit handicap, even if it's 9.9. Lol. These clubs are getting me closer than I've ever been. Thanks, Jim

No 2 shafts are the same. Flexes can vary. Even if they have the same characteristics. Typically, a shaft with a high kick point, firm tip, will hit the ball low with low spin. A shaft with a low kick point and soft tip, will hit the ball higher with more spin. There's also tipping. I could write a whole book about the various shafts, etc.. 

My suggestion to you would be to get a hold of your local Titleist rep and schedule a fitting. If you can get to a Regional fitter, they'll have the most shafts/options to fit you with. Advanced fitters will have some good stuff as well. That way, you can get a feel for the different shaft, loading, impact, and so on.