Diminishing Returns... yup, I’ve seen it. Like Rex said though it takes a lot of experimenting. Here’s mine:
I went with the popular thought of going up a flex for every inch you add. I forget the formula for head loft. Anyway I Put together some 5-7 degree heads with 48” xx or xxx because my normal driver was 46” x flex. I sucked... hit it shorter than my playing driver, all low cuts, nothing off the center of the club face. I gave up and sold everything.
A year or so ago I was watching the WLDC and I pay attention to the women’s numbers and look up their equipment ( so to speak). I saw that Troy Mullins used a 9 degree Ping head and a stiff shaft. I then saw Justin James hit it just as far with his 46” driver when his LD club broke. Got me thinking, especially Troy Mullins. I thought maybe I needed loft, so I put an xx shaft in a 9.5 degree M2. Nope, weird shots, kicked at the wrong place, felt like crap, couldn’t find the center of the face.
In the meantime I picked up a G400max 10.5 and was killing it. Spin, launch, distance and accuracy was nuts! Got me thinking of her again. I was fitted for a stiff shaft because of my transition so I stayed with the softer flex per my fitter... I could finally feel a shaft load. I picked up a 9 degree G400max head too and after researching Paderson I got one of their shafts. Talked back and forth with them about fitting and their suggestion of the stiff plus flex, uncut. Great advice!!!!
So I basically have something like Troy Mullins was using and we are around the same speed. So I needed to stick with a soft shaft and went up a half flex. Loft came down 2 degrees from my gamer to 8 degrees. I could probably do 7 degrees but that would be the lowest. Don’t have the speed... I pay attention to the women.