Terminal velocity is at best a dubious way to tune a load, and that's if you can measure it accurately. I won't say it's worthless, because you never know. There could be some minor effect related to external ballistics, but not related to individual bullet BC variations (which we cannot control with tuning, but we can control with sorting), although I'm stretching to find an explanation as to how that could be. How are we to explain how tune impacts terminal velocity?
Further, a large part of a rifle's lack of inherent precision is due to aerodynamic jump and cg jump - which are launch effects that are linear with range and have nothing to do with exterior ballistics. Getting a rifle to shoot under .3 MOA at any distance means getting this part right, and that's not easy. There are tons of rifles out there, including many customs, that simply can't get there reliably. No amount of tuning will mitigate these effects because they are random in direction and unrelated to minor variations in velocity. Fixing them is the purpose of good reamers, chambering practices, high quality bullets, good brass prep, good powder choice, sorting, etc - all aimed getting a good bullet to hit the bore straight and stay that way. Barrel vibration just isn't a credible part of that equation.
These effects are well documented by scientifically sound research done by the BRL and other similar organizations.
This is not an attack, just a critique of the method as described.