Some drivers (even from the same manufacturer) don't always work like you'd expect. If you are having a challenge with this, your best option is to bundle settings in a custom action within the Uniprint package. Instructions for this are found in our Customer Support Knowledge Base at http://pharos.custhelp.com/app/answers/detail/a_id/866. Pharos Help will be able to walk you through the implementation of the action within the package.
When dealing with 32-bit and 64-bit printer drivers, are there any special considerations?
Do we need to do the custom action for each flavor, for example?
Potentially. In most cases, the Registry locations are the same for both: HKEY_LOCALMACHINE\System\CurrentControlSet\Control\Print\Printers\..... But your mileage may vary.