Tour 75X with a 100 mph swing??? You’re a better man than I. Or, this is definitely Golfwrx.
Not better or worse, just load the shaft hard at the transition and have always done better with a stiffer and heavier shaft (Modus 125 x in the irons). I actually think that the Tour 75 shaft isn't as stiff as the Tour 65 shaft. The Ping rep said that since the 75 comes tipped 1" in the driver the profile changes and the 65 has more of the stiff tip left since it isn't cut. I thought the 75 S played really soft when compared with the 65 S.
If you look at the chart Ping makes about their shaft options, you can see that the 65 is actually a little stiffer than the respective 75 shaft though the 75 is heavier and has a lower launch profile. More interesting is that it shows that the Alta CB X shaft is even stiffer than the 65 and as stiff as the HZRDUS yellow 6.5.
Ultimately, since there isn't an industry standard on stiffness, I just ignore the flex rating and try to swing with an open mind and just focus on the results and dial in the flight I'm looking for. If you've got 9 minutes, check out this video on shaft flex that may make you think about shaft flex differently. Despite what you might imagine, an X flex may help increase club head speed.
As for Aoa, I am usually a +1*, but due to the rust it was a bit all over the place. Very well could be that my spin issues came when I was too steep and perhaps the heavier shaft helped me deliver the club on a more consistent plane. I haven't hit the Rogue, so I can't say, but the G400 series is a seriously forgiving line of clubs.
I play a Aldia Rouge Silver 60 Stiff in my G 400 that I played in my G and it feels fantastic. When the weather improved I'll probably try the Alta CB that came with the driver but my past experience was I spin the Alta too much but the ugly blue Alta CB that came with my G driver had to go anyway That chart is very telling and I'm surprised that the Kuro Kage plays so soft but admittedly I have only hit that shaft a few times.