Titleist 913 D2 Shaft questions

Hey TT,

I was recently fit into the 913 D2 , and I opted for the 10.5 over the 9.5 head for the sake of control and the over all reduction of side spin.

I am a taller golfer 6'2 , somewhat of a higher ball flight player, and my miss is generally left

with a moderate to smooth tempo that generates club headspeed of between 105 --108 mph on average , the fitter put me into a diamana d+ and or Matrix black tie 7m3 stiff flex .... I took the black tie and played it for about a week and thought it was just too much for me to load.  Will the D+ play smoother and slightly softer? remember I don't feel like I have a hard transition to the ball, but with these two shafts I do generate more spin with the Diamana over the Matrix

I believe the specs with the diamama were 13 degree launch, 3000 rpm  ball speed in the upper 150's .....

My question is why do people say ( on the internet) if you are smooth swinger the whiteboard generally doesn't work? should I have gone with the blue? at that rate i know my spin and launch numbers would only go up.  The D+ does feel very nice, i guess i should have tried the blue to see the specs on the LM but the fitter didn't even give me that option? I am just second guessing the fitting, though I feel the club plays well, just seeing if I am missing out on anything by not trying the blue

edit..... I am talking about 72 gram D+