Currently, there is no way to specify any dimension-specific settings when using the Geodatabase writer to create a dimension feature class. As a result, default settings are used. The default dimension style created by the writer is equivalent to the default one ArcCatalog creates. Likewise, the reference scale and map units are set to the default values used by ArcCatalog, 1 and decimal degrees, respectively. If the dimension feature class is created within a feature dataset, it will inherit the units of the feature dataset rather than being set to decimal degrees.
If the default settings are not sufficient, the dimension feature class should be created before the translation using ArcCatalog. ArcCatalog makes it easy to import dimension styles from existing feature classes and then change them as required.