Code:
UPDATE FILES SET Path = replace( Path, '/storage/emulated/legacy/', '' ) WHERE Path LIKE '/storage/emulated/legacy/%';
Replace "/storage/emulated/legacy/" with whatever your storage location is that you need to strip from the paths. You will also want to do this for audio files if you have those stored under the storage location. For that query, it would be
UPDATE AudioFiles SET File = replace( File, '<storage location>', '' ) WHERE File LIKE '<storage location>/%';
Let me know if you run into any problems using those queries. You probably already planned on doing this, but always make a copy of mobilesheets.db before running queries like that on it in case something goes wrong and you want to revert it.
Mike