Critical melody at http://omnigreg.at/wiki/doku.php?id=ant:1073 - the alleluia has many different variants in mss, I chose Lc, in conformity with Psalterium Monasticum 1981 p. 452. Note that Turco chooses Wc.

As often as I've sung this antiphon with the accompanying psalm (Ps 1, Beatus vir), the assignation of Mode I for the psalm seems not to work as well as Mode II. Thus have the monks of Solesmes used the Hypodorian rather than the Dorian mode for the same antiphon, in their 1981 Psalterium Monasticum.

I quite agree, mode will be changed to 2, see my version.