Leatt chest protector 4.5 sizing help appreciated

I think this one depends on what you want. I think many back protectors are intentionally only in the upper part of the back as that the most likely part you’ll hit when hitting your back (I think). When I was searching for back protector I found one which covers the whole lenght of my back because that’s what I wanted

Edit: i’m same height as you and I use poc system torso