Roe I was thinking about you and this thread at the range yesterday. I've been breaking in a new Muzzle loader and feeling like a rookie.
This one has a pistol grip type cutout for the stock.
It's not natural for me so it's taken a lot of getting used to so I was paying a lot of attention to my form and mount which reminded me of your thread. I felt like I was getting some torsion related to the angle of the pistol grip and worked on bringing it up and getting plum etc quite a bit.
It dawned on me that with all of my shotgun shooting that's never a consideration.
That is instinctive or reactive shooting though. You bring up the shotgun, get a good weld with your shoulder and then bring your cheek to rest.
I do that in the same manner as you demonstrate with bringing your head straight down and "resting" it on the butt of the gun vs pulling the gun into your cheek.
I found after thinking about it a little at the bench I 'm the most solid when I settle the butt into the shoulder first, then bring the head down to rest on it and indeed when I mount the rifle in this manner I'm almost always instantly plum and level and when I'm not I see it instantly and correct just as quickly and easily.
One of the best things about this forum is that it gives us all a chance and a reason to think through the mechanics of how we do things rather than just going through the motions without thinking.
It's like doing vs teaching. When you are teaching you have to think your way through every aspect of the subject matter vs when doing and just flowing through the process without really consciously examining what you are doing and looking for ways to improve.
Thanks for bringing it up.