Nice job, Atomic.
I've been making cured egg yolks for many years using a process similar to yours. I first learned of these and their preparation a few decades ago when I was traveling in Denmark and Sweden where they're called gravagg(aeg), or "graved" eggs. Obviously, the preparation of the eggs is essentially the same as the preparation of gravlax, salmon buried in salt to cure.
Many call for a 50/50 mix of salt and sugar but I omit the sugar as I don't see any benefit to it, nor do sweet eggs even sound appealing to me. Also, many call for a curing period of 5 to 7 days, but I don't think that's long enough. The salt's primary job is to induce osmosis and draw water from the yolk, which represents about 50% of the yolk's weight. With a short curing period of 5-7 days I've found that the yolks are tacky and still a bit damp or, in short, just partially cured, and will not grate properly. To overcome that issue, many call for putting the yolks in a low heat oven (150F-200F) for 1-2 hours to finish. That will do the job, but you're then cooking the yolks somewhat, which I want to avoid.
I always do a dozen eggs at a time and often leave half of the batch plain and lightly dust the other half with some type of a spice, or spice blend. For the most recent batch, which is just about gone, I used smoked Spanish paprika, Pimenton de la Vera. Other times, depending upon my mood, I may go Asian (dashi, togorashi, etc.), Middle Eastern (sumac, za'atar, baharat, etc.), or North African (berbere, dukkah, ras el hanout, etc.). From time to time, I may hit a few of the plain yolks with a dash or two of real, or pure, balsamic vinegar. From there, the top layer of salt goes on and the wait begins.
Depending on the size (large, extra large, jumbo), I cure the yolks for 10 to 15 days. When finished, I remove all of the salt from the yolks and place each yolk into small individual muslin pouches normally used for bouquet garni. The bags then hang from a rack in a utility refrigerator for 2 to 4 more days to insure final drying, if necessary.
Again, a great job and certainly worth a "Like".