Nick Müller wrote:

You have one caliper with one piston that pushes onto the disk with say
1000N. Now you take a second caliper with the same piston diameter and
slip it over the disk. You will get double the force, no matter on what
side of the disk the piston of that second caliper is. You can now make
a single caliper out of the two, without changing anything compared to
having two calipers.

Not if in making the single caliper out of two you effectively put the
cylinders in series.

The simple question would be, will the system still work if the
pressure line to one cylinder is removed and capped, leaving the
cylinder vented but preserving system pressure for the other one?