Another rule to maybe test out, is not to rest the forend on sticks or other rests directly. To put ones hand in between.

I noticed on a Cal Pappas hunting video in Alaska,he resting his .450/400 directly on shooting sticks. I asked him and he claimed it wasn't an issue.

Another shooting challenge "assumption" to test out I think.

I think a lot of these "assumptions" and "rules" are variable and not consistent across all firearms. Test samples might prove rules, or not, or variability.