Absolutely agree with kraigwy, but I think we learned from the same old school.
As far as the offhand position goes, this is the right way ( though you rarely see it at a public range where there are not competition shooters):
Bone support: No muscling. Rest your non-shooting, or support elbow on your hip bone, rib cage, or stomach, (depending on your build).
All bone support, no muscle. Elbow on hip bone, lean back to bring the sights up to the target; lock your back and hips. Look how these guy's offhand supports the rifle on the palm. You can also make a fist and support the forearm across your knuckles
How to shoot sporters. I personally would bring my right elbow down and tuck in to my side like the guys above
You can do this with high power rifles, 30 '06 no problem, just roll with the recoil. An AR, but the same idea...
At first, leaning away from the target may feel strange, practice and, after a while, it will be the only way.
The aggressive "art of manliness" photos are for an action shooting event, speed over accuracy. It has its place, though, and I wish I could shoot well like that for those particular situations