[GDH]

In your situation, there are two basic data recovery techniques:

Look for the old Master File Table, rebuild it and hope that the cpr files are still listed. This is what the "Complete Format Recover" does. You could try running a Complete Format Recover search over the entire drive for the default selected file types plus the RIFF file type - but I think you have already done this? - and look for your cpr files in "Folder View" of the results screen.

A by product of the above search is that files found and listed in "File Type View" of the search results screen are found by identifying the file header and footer - these are the files without original names (as file names are only stored in the MFT), i.e. Recovered_RIFF_1.