10point,
Not to be nit picky or a dink but
You have an adjustable cheek piece.
Cheek weld is the position and pressure of the cheek on that cheek piece.
I've found that consistent small groups come from a consistent cheek weld and consistent rifle butt to shoulder position and pressure.
Shoulder pressure on the butt as is 'loading the bipod' provides for consistent observation of hits. Last Friday I verified drops 2 502, 644, 977 and 1215. The 1 shot needed @ 502 was @ a 10 degree down angle, 644 was -4 degrees, 977 was 2 degrees and 1215 was -4 degrees.
502 shot was spot on first shot. 644 was a bit low first shot. A couple of clicks up and second shot was spot on. @ 977 I could spot the first shot but saw dust in the wind from the rock target. I got a little more serious and still couldn't spot the POI on the second shot but saw that I was hitting a couple IPHY low. Made the adjustment, paid really strict attention to the rear bag and shoulder pressure. Rifle simply laid there and easily saw the POI. The 1215 yard first shot was a bit high. Clicked down a couple and dusted the small target and was able to watch it disappear.
The nifty thing was that due to the position of the 1215 yard target the shot was taken left handed. The experience of the 977 yard shot made me pay attention to cheek weld and shoulder pressure.
Note that I use a solid bipod and loading the bipod is not a consideration but consistent butt/shoulder pressure is.
Cheek weld pressure and position is whatever is comfortable and consistent for the shooter.
I don't understand the pillow thing as my entire head weight is on the pillow.
Also I don't use adjustable cheek pieces and only a soft touch of the cheek is necessary to get a full view through the scope.
Just sayin'