4th,
Good post with pics. I think that with these lightweights, < 7 #'s, whatever is a "real world" shooting scenario is what you should practice. Whether its leaning against a tree or post, off the top of your pack - sitting and prone, etc..
The next heavier contour on the Montana would alleviate a lot of this. Let's say a .625" from a Tikka for example.
We look forward to your next range sessions.

My home is the "sanctuary residence" for my firearms.