I had a similar idea applied to my situation (partial suspension hanging) which I've yet to try with the intent to die but have fielded positive results in trial runs. Since I was struggling to release enough weight into the noose fast enough to shut my carotids, I tried something new to do it for me. You're thinking an inflatable bed (very creative) and I tried out an office chair. I would position the noose as necessary. Then I'd just sit in the chair (which was inherently less daunting) and when I was ready, fully let down the gas lift. I was able to recreate the familiar sensation caused by successfully closing both my jugulars and carotids. I just had to be careful that the rope didn't pull up uncomfortably on my windpipe.
As is true of all variations of partial hanging there's always the option to abort, which you won't have the option of if you decide full suspension as you've described. I'm wishing you all the best OP