Here are two things that I have done.

One, I use a Loggy and only use the bottom part. I hug the tree and shimmy up to my spot. The stand can handle 18" in diameter but my grip can only do about 16". I have used a strap to help grip around the tree and get up there. I've used a strap as well on smaller trees just to make it easier.

Two, I always carry a few steps with me to overcome lower obsicals such as split trunks, limbsand fat trees. With a few steps, you can get up several feet off the ground, one time I did ten, and mount then your stand.

Good luck