> Hi,
>
> I'm designing panels in Doepfer format. Can I confirm that they
> should be 2mm thick

Yes.

> Second, when making up patch cables, is it necessary to wire the
> sleeves as well as the tips My thinking is that all the sockets are
> ultimately joined to ground.

As long as connections are made only within the A-100 only the tips would be
necessary as the GND of all A-100 modules is made internally via the
bus/power supply. But if you want to connect a module to a device outside
the A-100 (e.g. filter output to an external mixer, or filter input from an
external audio source) the GND connection is required.

Best wishes
Dieter Doepfer