I am trying to find out more information about SPCopyFieldMask. Has anyone
here used it? I assume I can apply a mask to fields of an SPListItem so
that I can make copies of Source Items without copying metadata to Copy
Items.

The project I am working requires copies to be made of documents, but for
those copied documents to have different metadata (ie. for sequencing). If
I update the Source Item and use the Send To / Existing Copies to update the
content for the Copy Items, the metadata gets updated as well.

I have tried applying Masks to both the Source and the Copy but each time
the metadata is getting overwritten in the Copies.

I'd appreciate any clarification on this API in case I am simply doing
something incorrectly.