I am not the best shot in the world, and shake like a leaf in a high wind, so any time I have to shoot over 100 yards, I try to find a rest of some sort in the field. I have learned where to break the trigger in my wobble, and it works for me, but is not the best option. And I can say that I have taken offhand shots over 100 yards only on a few occasions, and only once over 200 yards on a large bull moose in a grown logging block where I had no other option at the time.
I have a Bog Pod Tripod, and while pretty stable, it can be awkward on a stalk, and is not as stable as I would prefer.
I also picked up a short tripod that has an arm for the back of the rifle. From a sitting position this does work pretty well, and have used it to practice out to 500 yards. I do find that having a back support also helps, so I try to sit back against a tree, log or rock when in the field.
I have a single trigger stick and a tripod trigger stick. The single stick works better for stalking and doubles as a walking stick, but is pretty unstable; better than off hand, but not by a lot. The tripod stick is quite a bit better. When sitting, I again try to find a back support and/or support under the rear of the rifle for even more support.
I have seen where people are hunting in pairs or more that where one is using the tripod and another is using the single, when one has a shooting opportunity, the shooter sets up on the tripod, and the other assists by placing the single under the rear stock of the rifle for added support, whether standing, kneeling or sitting. Seems like a method to try for additional support, provided the shooter has the time to set up for the shot.