@cripplejuice
I am not sure about this and others are welcome to chime in to correct me but I have been using serum ceruloplasmin as a marker to gauge my copper status.
As I understand it is hard to find the right dosage for copper supplementation, as you very well know, I decided one day to just incorporate a food to my regular nutrition (or diet though I abhor the word diet) but before I began on one year of eating that food, I took a ceruloplasmin test and it turns out I am on the low end of range, the range being 18-32 (I don't recall the unit).
I ate a small crustacean in the form of a pasty sauce for a year. The crustacean is common in southeast Asia and called by different names. In the Philippines the crustacean is called alamang and the pasty sauce is called bagoong (belacan in Malaysia).
I took the test again after a year, and my ceruloplasmin went up to 31.
Note that Peat recommends shrimp for its copper content. But I don't like farm raised shrimp as it's known for being raised with antibiotics, and I don't like the idea of eating such shrimp regularly. Wild caught saltwater shrimp would be ideal, but they are hard to find nowadays. So I settled for the small crustacean.
