You can actually accomplish what you need in this scenario easily.
1. Import the roms and select 3D box for all games.
2. Once import/download is complete run the audit option on the platform.
3. Sort the 3D box column so you can see all games missing 3D box.
4. Highlight only those games then run the media wizard on only those games and select Box-Front. Now the wizard will only download box fronts on those games you selected that were missing 3D Box images.
I know you are making recommendations, but there is an existing way to do what you want.