Hi Rian,
never did such bleeding test on a S model, but I think it will be a part of "special funktions"
and maybe only done by connecting your wifi GS directly.
Brake fluid in the system, by adding all hoses, cylinders and fluid reservoirs, just around 300 ml.
After flushing and bleeding the system, there will be a usage of 1 Liter DOT4.
Stahlflex brake hoses doesn't have any date of expiry like rubber hoses have.
Please check them for external damage every service