Wedding photography backup

As a photographer, I may be shooting three or four weddings per week. That can equate to thousands of images. Lately, wedding clients have been asking me how do I protect all their precious images from getting lost or deleted accidentally. Well here goes. At an average wedding, I may shoot 700 to 1000 images all recorded in RAW file format That is an awful lot of memory space.
Shooting with a Nikon D4 I have the option to record onto a dual card slot system, one a Cf card and the other onto XQD format, one backing up after the other or I could record one in RAW and the other in JPEG but for peace of mind, main and backup. So at least if the Cf card fails I have the same images on the XQD card. In the last three years of using the D4, I have only had one instance of partial card failure, that CF card stopped recording after 115 images, luckily the XQD card saved the day and the guilty CF card was instantly resigned to the bin. Once the wedding is over and I’m back in the office, I will upload the card to lightroom, convert it to Digital negatives and then from there export as a catalogue to three external hard drives tagged as “backup” and then to another three external hard drives and tagged as “edit file”. With one main drive from which I work for the editing. Create a desktop folder with the client’s first names and date of the wedding and edit all the completed jpegs into that folder. Now lots of other photographers have their own ideas on how they back up and tag their images, ie, by date or times, etc, my workflow system works for me and I can edit a complete wedding of average of 800 images onto a folder of approx 350 to 400 images within a few hours. From there the completed JPEGS folder is again backed up onto two separate hard drives solely for the storage of JPEG files. Once all the backups are completed onto their multiple redundancies drives then and only then will I reformat the CF and XQD cards. From there I will export the complete JPEG folder to my online gallery system.