You are overthinking it. You are basically going to have such similar shafts by hard stepping the 6.5 or softing the 7.0 (both in flex and more importantly in weight), that if you can hit one, you can hit the other or vise versa. You will get much more definitive results from bending the lofts to adjust trajectory.
You would really need to move into a different weight class before I would say you would see any noticeable difference over the long haul between shafts.
Coincidentally, this article came out and lists a lot of what we say in LSW and so on. Scoring lower again involves:
Not taking penalty shots.
Not taking doubles or, when you get better, not making a bad bogey. (You're still going to make some bogeys.) Playing for pars and letting the birdies happen is tough for people to get.
Understanding where to miss the ball and fitting the "better side" into your shot pattern/Shot Zone.
The last part answers your question of sorts: If you can develop a ball that only curves or misses one direction, that's a pattern. You can play a patterned Shot Zone much more easily than you can play a "fern" Shot Zone (where the shots have a root and then spread out in all directions from there, two dimensionally, like a fern). I'm not sure what "fighting" a one-way miss means - if the vast majority of your shots are, for example, missing left, either open the face to take off some of that left miss/curve or just aim right and play it. If there's trouble left, aim WAY right.
The smart-player's guide to dropping 10 shots — guaranteed
Improving at golf doesn't require hours of range time. Recreational players just need to take advantage of the stat-based scoring opportunities out there.
Things like this are why I initially brought the question up. I have nowhere to try these on. I spoke with FootJoy and they stated that you buy according to your normal waist size but that those sizes are made with the assumption that they are going over the top of your golf clothing and are sized a bit bigger
I’ve been driving the ball a lot better the last two rounds. I’ve had drives range from 220 to even 260. Yesterday I had an uphill drive of ~250. I’ve worked on ball position having the ball at my front big toe. This has been taking off spin and launching higher. I lower the loft on my driver as well. Below is a practice from two days ago.
Long irons haven’t been as good though. I am missing left with too much draw. I will work on ball position there as well. Short irons have been DOBA, especially with 3/4 swings. Yesterday my 3/4 9 iron and PW were spot on target. I feel like I am not hitting down enough on the long irons and coming in shallow, but this swing is better.