RE: What has been your most common shooting position for rifle elk?
Funny thing is a lot of people pratice shooting. But few practice shooting properly. My dad is a former Army marksman, I was lucky or unlucky depending on your perspective. He taught me the proper position and the proper use of a sling. A sling is an instrument for improved accuracy not a way to hang you gun over your shoulder. If you use a sling properly you can do away with rests, bipods, shooting sticks, and the like in most situation.
As an example most people shoot in the prone position like they are laying on there bed. The proper prone position is rest on your knees and elbows slighty raising your belly off the ground so that your breathing doesn't push you up and down. Its almost like a mini pushup.