I have a similar approach, I have ripped all my most precious CD's using EAC secure mode to FLAC with non-compliant CUE sheets. I have these on an External HDD and have also burned ISO DVD's which I keep in a fireproof safe. You can get between 15-20 CD's on one DVD. So in case I lose a CD or the HDD fails,,,all I do is load the ISO disc and copy the files to the PC, then open EAC select the burn CD, enter the CUE sheet I made and you get a "Perfect Copy", of your original recording.
EAC = the best free application for ripping I have ever used. It's complicated to set up but once you customize it for the burners in your computer, the results are the best MP3's you have ever heard and FLAC's that are perfect replica's of the original WAV files. I would recommend it to any serious collector as a way to safely back-up your collection.
LG you are such a Boffin........