Critical melody http://omnigreg.at/wiki/doku.php?id=ant:0610 with a realization following Zw and Sandhofe for the first member. There are very many legitimate variants.

Switched from 8g to 8c. Both transitions are OK, the mss are inconclusive because most begin on SOL and not DO, and the next antiphon is 8g so 8c is better for variety.