I have a Teeter. it clamps at my ankles and my arms balance it. Then I gradually tip over backwards toward upside down.
It has a safety strap and I stop it before vertical. Look up at the ceiling for a minute or more then my arms balance me back
to normal. It takes a spotter at first to get The Teeter set for height, it adjustable, then good to go alone. It also has 2 side
handles for added ability to stabilize. Maybe I'm wearing a heavy hoody. The Teeter is sort of like the Monkey Bars of youth.
Gradually learn the art of balancing it with your arms, don't fling your arms up over your head. Slo up some and feel the balance.
there are Video on YouTube. Sure, body perfects but getting the idea is important. My Back usually cracks on first tilt, then shoulders as I hang upside down flexing. You set the Ankle clamps snug and you don't move much in them. Work Boots work well also. Just stay in balance when up righting also. Slo is the main word. Much safer than the Monkey Bars of Youth.

The Teeter Inversion Table. Same Shoes / Boots and Shirt type is a great way to learn its great help to you. I feel like a new man after a half hour in it, get out and walk around. I teeter back for a minute and then back upright then repeat. The tools that mount on it are individually adjustable. You feel the cracks. I would recommend it for most
average people. Very heavy would most likely not be comfortable with one. Just a Thought though. It Slides / adjusts for the individual height
and locks in that adjustment with a large spring-loaded pin. Teeter needs an open 8' x 4' space. Even the garage will do. Ships free with Amazon Prime, & is easy to assemble. Our home has Lofted Ceilings and that makes it even more fun to use.
I adjust the tilt safety strap to hold before being completely back vertical. I don't feel the need to do the Bat Thing. Guess they are wise with being upside down a lot. You know imediately if it helps & you like it or not. Most average people like it. Just want to try before purchasing are many thoughts. I watched the videos and bought. I love it. Mine was less than $400 delivered in a large box. I put it together. 3 years.
now. My wife wouldn't / couldn't use it. She was very uncomfortable on it. A hunched back might not be able to do it either. Average would be the word. A fairly decent Spine needing decompression is the go for it. There are also Seat Spinal pads to set on, pre formed just set on seat for those who are at the keyboard hours. I also have one of those for my office chairs.
Setting up, not setting low to the floor, also not sloppily is the action verb. The Electric rise / lower Desk is a great work tool. + Dell 32= curved screen monitors with the Dell Optiplex Light puters.