Hi Sam,

Adam played a week with the 10.5 and went back to the 915 D3 9.5 head.  The 915 head does offer less spin, but there are several ways to get less spin when designing a head.  Our engineers were able to keep the CG back which helps with forgiveness and ball flight.  The 915 does not fly lower due to its lower spin.  In working with players, we have seen it fly slightly higher than the 913. 

Sam, I spoke with Bubba about this in Chicago a couple weeks ago with my own situation and tomorrow I am at Oceanside TPI Facility so it seems the answer is "no" but rather where on the face contact is made as well as getting the right trajectory...while I am not in the same class as Adam Scott my experience last year I moved from 10.5 913 D2 to a 8.5 913 D2 to a 9.5 913 D3 as a result when I hit the 915 it appears that the 8.5 915 D3 is my leading candidate, so my point is that over time a person's swing or preferences may change slightly.  This also could be a result of a ball change, i.e. the new Titleist ProV1 ball or other factors.

Basically, lots of variables and no black/white answers.  

Hope this helps, Chris

I agree with Chris92009.  There are no black and white answers. Our swing changes and we unknowingly compensate for nuances in our game. 

There is just a ton of technology in the 915 Line and I am sure there is a permutation to fit for your desired golf goals and preference.  I, myself play a 909 D3 9.5 with Diamana Whiteboard and was fit to a 7.5 915 D3 in C2 (6.75 degrees) setting with D+ White 80. Surprised and shock were a couple understated reactions I had once completed the fitting.

I imagine the 915 D3 7.5 coupled with the new 2015 Pro V1 will be a highly effective combination to attack the golf course!

Good luck and play well!