WRT using the sawbench as a stool, I’ve built a handful of these following Christopher Schwarz instructions. Those sawbenches are outstanding exercises in hand tool wood working. As fantastic as they are to make, the design has some inherent flaws that make them exceptionally unstable if you place the slightest amount of weight near the legs/ends.
I would go so far as to say the C.S. design is literally unsafe. I’ve marked the outboard section of my benches with red warnings to help prevent injury. I should rebuild them in a safer more stable version, but I rarely have anyone else in my shop.
Just my experience specifically with th C. S. design.