Actually ended up reading "Black Flag" during Sorrows of Empire
and I'm glad that I did, because it makes the Vanguard story arc in Sorrows
a little more complete. As well, Swallow appeared to be aping the style/pacing of Mack's story, and it fit fairly well in. Clearly a little different, but nicely done. About 50% through Sorrows
according to my Kindle and I'm loving it. Might be my favorite Spock-centirc tale.