Looking at your original post, you have only tried 2 different loads using flat spots in your ladder? I would try a few more. Just choose one of the two and work up and down by .2gr.
If I had to do one thing case prep wise after sizing to improve ES, it would be use a mandrel to set neck tension. So I either use a bushing die or a full length without the expander ball. Then I run a mandrel in the necks. I also recommend flash hole deburring if you're not using premium brass and possibly primer pocket uniforming.
I would start with the charge weight. Next I would tweak seating depth by .003" so say you end up with an SD of 12 with 43.1 gr seated .015" off, I'd try .012", .009", .006", .003" and the other way, .018", .021", etc... you'll be surprised what happens at .003" at a time. Once you find what seating depth you're bullets like, you can tweak powder charge again.
Lastly, I would experiment with primers.
Some bullets are very tolerant to jump, some aren't. Good luck.