LSJ:
No Euripidean citations, but still . . .4. of places and things, γῆ εὐ. ἐναγωνίσασθαι favourable to fight in, Th.2.74; εὐμενεῖ ποτῷ (of a river) kindly, bounteous, A. Pers.487; of the air, mild, soft, Thphr.CP2.1.6; so of medicines, beneficial, “ὑποχονδρίψ καὶ σπλάγχνοισιν” Hp.Acut.59, cf.Aret.CA1.3; but also, agreeable, [“κόμμι]-έστερον κόλλης” Hp.Art.33; of a road, easy, X.An.4.6.12 (Comp.).
Luigi Battezzato, in the Cambridge Greek and Latin Classics ("green and yellow") series, defends the repetition and prints πρευμενοῦς in l. 540 without daggers.