It is not true that the 4350s are more accurate than other powders that don't fill the case. It's a classic misconception because of not telling the full story.
Here's what I found out:
I own a .30-06 Tikka and load 150 and 165 grain bullets. My 165 grain load is a full case of AA4350 (57gr or so, slightly below max, too lazy to look in my papers) behind a Hornady Interbond. That load shoots 1 MOA.
my other load is 50 grs. of VV-N140 behind a 150gr Sierra Pro-Hunter. This load shoots .25 MOA despite having much empty space in the case.
All else being equal it is better, more accurate to have a full case. In practice often other things matter more. N140 is significantly more offensive than 4350, so it's obviously far more accurate because there is much less turbulence when the bullet leaves the barrel. The more progressive the powder the more likely the powder is still burning when the bullet leaves the barrel which causes turbulence at this critical moment.
Vihtavuori claims that N140 is the best powder even for 168 grain bullets which is probably true, N150 (their 4350 variant) is only mroe accurate from 180gr onwards.
Despite that findings I still like AA4350 better. Yes, N140 behind the Sierra is far more accurate. But this is a hunting rifle, if I wanted accuracy I'd use Matchkings.. As it happens hunting bullets are far more inaccurate, most of the time even more inaccurate the more expensive. That is because complicated bullet design causes inaccuracy. The Hornady Interbond is a fine unting bullet, bonded, thick jacked. But there is no way this bullet can ever be as accurate as the Sierra with it's ultra-perfect consistent thin jacket. And there's no way the Sierra can ever perform as well on game at all velocity ranges as the Interbond.
In the end we musn't forget that we load for a hunting rifle, it's a tool. If we sacrifice performance on that goal for accuracy gain we are making a mistake. It would be accuracy with no purpose.
Accuracy means for me I choose the components best suited for my hunting goals and then try to optimize accuracy with these components. A good hunting load with 1 MOA accuracy is far better than .25 MOA with a compromised load especially considering 1 MOA is more than I'm capable of shooting when under stress.