: One thing that we have learned about the
: automatic Carreras, in general, is that we cannot establish
: which tachy ring belongs in which execution.

The very earliest watches consistently have the Tachy at 3 bezel, but that seems to be all we can reasonably conclude. Once the Tachy at 1 bezel comes along, it seems the more common but they are used interchangeably then. Only seems to be on 1153s though, Tachy at 1 is very dominant on 1553s and looks to be the only one used by the time of the 110.253. Though the latter is such an in-house parts bin watch, you never know!