Attic files should be left as-is. The converter will import them as they make up part of the history, but their head revision should be deleted. However, they are included as part of the label/branch detection and so may show up again.
If you have a single example Attic file, please run it through the converter then send me: the file, the result and what you would expect.

Here's what I found: A couple ",v" files show up in both the ATTIC as well as the repository. Based on my understanding this is not a valid situation. They should be in one or the other - not both, correct?

I think this is the source of the problem I'm seeing.

Let me know if you want to pursue this.

A ",v" file with the same name in the ATTIC and regular directory will cause the converter problems. I wonder if it resulted from a case rename 'foo' to 'Foo', but perhaps the OS flattened the file?

I could add some code to protect against this situation, but how to handle it? Ignore the ATTIC file or stop and raise a warning or perhaps try and merge the RCS entries?

Could be a change like that - hard to tell.

I would suggest recognizing it and raising a warning. A stop may be appropriate since without that file the import really is just a partial one.