John, Mackerel isn't my favorite fish, but you nailed it! I love grilling fish (unless they stick.....my fault, typically, but still a pain!) Did some salmon the other night, and it was delish!
Nice work......a relatively short, high heat burn would decontaminate your E6......then again, since you have a 26'er, what the heck! I don't think my wife will buy the notion that we need a dedicated fish grill, but I can try.