Look at the two bearings which come with the Cane Creek S2 headset ... there is the equivalent of a 'rabbet' on one side of the inner diameter & 'shoulder' on the reverse side which will allow the two bearings to nest against each other if put together ONE WAY, and not in any of the other ways ...
The crown race has a ridge/"shoulder" onto which the bearing will nest.
On the Cane Creek C2 headset, the chamfered outer edge of the bearing assembly faces UP.