Hello Al; You have a bit more experience in this world than I do, but other than that, we're close. I'm about a 15 handicap and was fit this Spring for my 915D2, and according to the Trac Man I was swinging at 79.2 mph. (I may be a little faster now that I've played some, and at my fitting I hadn't swung a club since last Fall) My fitter was a great guy and he suggested the Diamana Red 50 in Senior flex. Just my opinion, but I think the "A" flex would help you a lot as it did me. (although, I was hitting an "A" in my previous driver) Most important, if you can at all, get fitted from a Titleist fitter before you buy. It may cost a bit to get fitted, but if your going to spend the money for a new driver, you need to get the right one for you. I learned so much from my fitting. I've always had a problem with a slice, and the first thing my fitter told me was that my standard 45" driver was too long for me, and that is why I was slicing so much. (I couldn't square up the club face with that long of a shaft) He cut my driver down to 43", and now my slice is gone, and I've gained a great deal of distance even with the shorter shaft. Even have a slight draw now. I really think the Diamana Red 50 "A" flex is a shaft you should consider but get fit first if you can. You will be glad you did.

Agree on a fitting. The biggest variable between the 2 shafts is launch angle and backspin. The 2015 S+ (blue) also has a lite ("senior") option. I'm in the mid to upper 80's and thought the M+ (red) would work for me, but my back spin numbers stayed over 3000 with A and R. Have a R flex S+ that works for me. I don't want to jump to conclusions on whether you are using a 10.5 or 12 degree 913, either. Note the M+ also has Lite, R and S. While the stores may only carry S+ in R and M+ in A, Titleist is far more flexible than that with the fitting carts.