When I trapped wolverine in Alaska, I would build natural cubbies using dead spruce and alder as a frame, then cover that with spruce and hemlock boughs. A proper cubbie took time, and not just any old place would do, as southeast Alaska's weather was a constant battle, with freeze-thaw considerations a priority to manage. And securing a trap that would keep a wolverine where I could find it after getting caught in a trap meant, at least for me, securing it to something solid. I never considered using drags, even though there is brush aplenty where I trapped, (it was so dense, an animal could easily "vanish" in it), there was also open tide flats and beach, and if a wolverine made it there, I would never find it.
I learned the hard way that chaining the trap to a nearby tree resulted in a demolished cubbie, as well as a very large excavation where the cubbie used to be. So, when selecting a place to build a wolverine set, I would obviously want to find a place that I thought a wolverine would happen by in its extensive travels. Then I wanted ample material for the cubbie. And then, not only a proper tree to anchor the trap, but another tree about 5'-6' away from the set. That tree was specifically for the wolverine to wrap the chain around, preventing destruction of the cubbie, and reducing the backhoe effect those buggers are so adept at.
I always had a crunch-proof or wolf swivel welded to the D-ring at the trap, then about 6" of #5 straight link chain with another swivel welded shut. From that swivel, I attached 10' of chain, which was a pre-made shot consisting of a quick-link, 6" of chain, a swivel, then 9-1/2' of chain, ending in another quick-link.
The trap-end would get attached to the short-chain-swivel end of the shot of chain, and the other end got wrapped around the anchor tree, near, (or usually part of), the cubbie.
Every single thing between the cubbie and the tree designated as the "wrap up tree" was removed. I wanted nothing possible to hang that chain other than that smallish tree.
It worked pretty much every time. The gulo would get pinched, spin around and run, hit the end of the chain, and run in a circle, pulling away and wrap up. It was obvious from the spun-up chain that after one wrap, it would roll and spin, then do another wrap, etc., until it was wound up within a foot or two to the tree. Those swivels close to, and attached to the trap itself, were the only things actually swiveling.
And most "swivels" aren't really that good at spinning freely. Take your set-up out to the yard and secure it to a tree. Then snap your trap onto a stick the size of a coyote leg and do what you think a trapped coyote would do. Then observe just what each of those swivels you think you need is really doing. Swivels mid-chain on long shots are un-necessary. Swivels on the business end are important, and near the anchor end are equally important. All these other "formulas" are non-sense.
