I have a 913 D2 with a regular flex Blueboard 62 gram shaft, extended 1/2 inch and then back-weighted to bring the swing weight back to DO. I love this club. I am a 9 handicap, 82 years old with a swing speed of 80 mph. I am contemplating purchase of a 915 D2, which I would probably extend and back-weight similarly to my existing club. Do you think I would gain length with a Diamana Red +50 senior shaft, rather than a regular flex shaft?