Hey Kix people - thanks for the great responses.

I found in my case I could accomplish my goals easily within the AD MMC.

1: In the search tool, add the custom attribute 1 to my columns.
2: "Find Now" all users.
3: Sort by custom attribute column.

since in my case the goal was to move everyone without data in this field to another OU....

4: Select all accounts without data in the field.
5: Right Click - select Move, select new OU

- Tada !

But thanks to Kix for getting the data into the extension attribute in the first place.

Thanks Again
Gerald