Here is a Notes Migrator for SharePoint Source Data Definition which you can run against any Notes database and get an idea of how big each of the records is, what the attachment size is, etc.  It does not load the actual attachments, rich text fields, etc, so it should be quick to run against the entire database.  You can see the results in the Preview, or export it to an intermediate file. 

On the Notes Migrator for SharePoint “Notes” tab, load the database and, if prompted to load the default data definition, say “No”.  Press the Load Data Definition button and browse to select the attached DataSleuth.pmsrc data definition file.  At this point you can Preview the job or press the Run Job button to export the entire data analysis to an intermediate file.

If you are attempting to debug a migration job that is not doing what you expected it to do, this is a good way to look at the shape of the data you are feeding into our tool.  If your “problem job” is specifying views or selection formulas, edit the data definition and specify the same options on the Select tab.  (This will ensure that you select the same records in the same order.)  This job exports no sensitive data, so no one should have a problem sending it into your support rep, etc., if needed.