I've made several slings from a 1" belt blank and fix the length to suit me.
On a levergun, I don't like to wrap in like I do with my Garand and crankbolts. On my leverguns, I sling 'em muzzle down. From there I can get them into action faster than I can my sidearm. For a hunting situation, the most steadying I go for is to rest on the side of a tree... if there's time.