My suggestion is not to concern yourself with shaft weight instead try to at minimum to  level out the launch angle and try for a little positive angle. That launch should be at least 12 and 14 would be better. I just went through a fitting for my 915 D3. I obtained 2200 spin avg. 120 side spin avg. 12 degree launch. +1 launch, computer said 235 carry and 265 total. I used it for the first time yesterday on course and those numbers (carry-total) are not accurate. I was hitting everything at least 10-20 yds past that on carry and almost not roll. 250-280 would be more like it. Anyway, I tried every shaft they had and the 60 gram was all over the place, I hit the X stiff and stiff 70 best. My macho wanted to go x stiff but my age (60) says I will "grow" into the stiff. So try them all on a launch monitor but get rid of negative angle of attack before you buy one. Lots of ways to do that but without video I can't say which one to try. Just my 2 cents worth. Good luck

Make sense, Perry. My neg attack angle has creeped into my game in the past few years. I guess touching 50 years old affects my game. Haha.  True, though, getting that swing flaw worked out will definitely improve things.

I emailed the person who with me and asked for clarification on the 70 over the 60. Below is his response. It seems to match your sentiments and experience:

"We went with the White 70 over the White 60 because there was not a difference in your swing speed or ball speed in the 70 VS the 60. Therefore, you could handle the extra weight and the shaft did not become so heavy that it affected distance. The 70 will also promote a slightly flatter ball flight than the 60 which will be good for your spin numbers. Also, a slightly heavier shaft should lead to a little tighter dispersion."

Paul