Help Ideal rope for hanging

[Hangman.]

My main goal is to compress the carotid arteries because I will attempt full suspension hanging and want to lose consciousness as soon as possible. I will use the window grill made of stainless steel as an anchor point.
Which type and thickness of rope would be ideal for this?
Also, should I trust random companies on Amazon for it? If you know any trustworthy companies, please mention them.

 

[Hangman.]

I have decided on static nylon rope with 1.5 cm thickness for now because it provides exceptional strength and minimal stretch. But I am quite skeptical about the thickness which will provide great amount of pressure on the neck without that much suffering.