I'm right there with you man.
Why don't you try an A shaft and post how it works so I can use your experiment's results with out having to experiment too. You'd save me from the $ /effort?? Naw, I'm gitin' too lazy to change again and I'm thinking my old Ping is giving nearly all distance I'm going to get.
Seriously though , I had a factory TFC ? Ping R flex shaft in my 12* G15 , soft tip from v good professional fitter to help my distance 5 yrs ago when swing was nearer 90s which worked a while, but not lately and I broke it mi"shit"ting it. I added 3 grams lead tape to bottom tail which may help raise it's trajectory a little .
I have also tried the 12 Cleveland 270 UL driver/Miyazaki 50 g R flex shaft cut to 45". Most of time my old 12 G15 I reshafted with low buck r flex 55 g Mitsubishi Rayon wins the straight & longer contests . Any drive over 200 carry is a happy thing. 3 or 4 times a round on good days. Nada on not so good ones. Thinking of adding some lead tape to the Cleveland to see if pushing it's weight up to about 290 grams works better for me . Still waiting to give the Miyazaki shaft some more chances . I'm working on my swing too, but much change at my age is kinda slow tough.