Optics question/technique?

[Texas Solo]

I need a little help understanding my optics, or more to the point, what I'm doing with them.
I added a scope level to my rig and squared it up via a level on the action while looking through the scope at a perfectly vertical line I have painted on my fence. That's when I noticed that i seem to cant my head over to the right a bit and the crosshairs will cant as well. If I concentrate on keeping my head straight on the stock, everything lines up....now anyway, as I rotated my scope the smallest amount to get it right. I feel a difference in my neck too. It seemed more comfortable to lay directly behind the rifle, rather than off at an angle like normally did. Maybe that's why I was canting my head?

I guess what I'm asking for is the best method of obtaining a solid, repeatable cheek weld & head position.
I do have the scope mounted at a good comfortable height and the eye relief is perfect. Parallax is set at whatever distance I'm shooting at (usually 600).

Can someone school me on some basics of proper set up and alignment? Things to practice?

Rifle is a 308 in a Chaote Tactical stock with Vortex PST FFP 6-24x50

 

[Lapua40X]

Eye relief and scope height will influence how you hold your head to align the sight. An adjustable cheek piece on the stock often helps correct the problem.
Also, in any position (especially prone) if you're not aligned directly behind the rifle (in a straight line) you are more likely to have to lean further over the comb of the stock to align the sight.

... when I noticed that i seem to cant my head over to the right a bit and the crosshairs will cant as well.

Suggests to me that your cheek weld is far too heavy and applying pressure to the inside of the stock or you're trying to align the sight by torquing the rifle into position; neither of which contributes to good accuracy.

 

[Ledd Slinger]

Find whatever is comfortable, then while making sure the rifle and optic are level and parallax adjusted correctly, do the same thing every time. Lot of different ways to shoot. What ends up on the paper or in the freezer is what really counts.