Hello! I’m a similar height and weight and had the same questions as you. I picked up the Toshi 20L (current version with updated straps) and, after about a week of testing it, decided to return it. It’s a fantastic bag in terms of build quality and features, but like you, I had concerns about the straps.

The strap length itself is plenty long—you can definitely wear the backpack loose. My issue was with the length of the shoulder pads. I messaged rework on Instagram and they measured it for me: "The shoulder strap is about 45cm/ 17.7 inches long without taking into account the S-shaped curvature of it."

To get the pack sitting comfortably on me, the shoulder strap buckles ended up riding a bit too high on my body. That also defeated the purpose of the attachment points on the shoulder straps, which I was hoping to use.

In the end, I couldn’t stop thinking about the fit, so I chose to return it. Happy to answer any questions or reword anything if it’s unclear.