Ergonomic chair recommendation for skinny people

Hi there,

23M here. Since we are all now traversing the coronavirus outbreak, a lot of people are now working from home, including myself. I am a programmer and work on a chair more than 10 hours a day. That being said, it would be a good time for me to get a good chair before I develop more serious back issues.

The chairs I was looking at right now are the Herman Miller Aeron, Herman Miller Embody, Steelcase Leap V2 and Steelcase Gesture. The problem is, because of the outbreak, my local dealers are now closed and I can't find any place where I can demo them (even in the used market). However, they are offering really good deals to compensate (more than 40%), so I could try and refund. Still, I would ideally like to pick the right one on my first shot and avoid all the hassle.

There are already a lot of threads online about these chairs. However, there is a serious lack of information regarding morphology. In fact, most people are on the heavier side and I'm a really skinny dude (6' tall, 130 pounds). Knowing that I'm an ectomorph, my back has really few support from my muscles when I sit and my intervertebral discs are crushing each other prematurely (i.e. osteoarthritis), leading to back pain. Also, I can't lie down completely flat on a hard surface because my spine comes out from my back, leading me to turn sideway to avoid direct pressure and pain on my vertebrae. Finally, my butt is plenty of bones and has no fat, so I need some cushions. Rest assured that I'm healthy, do sports, eat plenty and that I'm only the result of generations of slim people (mom and dad).

Knowing all that, I wouldn't be able to be comfortable on a chair that is really firm, which seems to be the case with most ergonomic chairs in this class. So, I would like to have some advice from people who have experience with these chairs and are skinny. It might help me pull the trigger on something. Cheers!

EDIT: I finally bought the Leap. I have contacted Herman Miller and they literally told me to not get an Aeron. Since I'm less than 150 pounds, they said that the mesh would be too firm and that the chair was meant to be shaped by the user, not the opposite. As for the Embody, they said it would be a better fit, but that it would be less appropriate for me in an upright position since the seat had close to no padding. As for the Gesture, I quickly realised online that it wasn't as good of a chair as the other three (in terms of lumbar support and adjustments). That left me with the Leap. Initially, I was scared that the padding would be too firm and that I would feel the lumbar support too much, but finally, it's just extremely comfortable overall. I would recommend it to anyone as slim as me.