Devoted Combo is a fellow combo deck trying to assemble Devoted Druid plus Vizier of Remedies for infinite mana, so the extra Veil of Summer copies are valuable to protect your own combo turn from their sideboarded Fatal Push, since Veil gives you and your permanents hexproof from black and blue. Note that Veil does nothing against green cards like their sideboarded Endurance. Elesh Norn, Grand Cenobite is a strong top-end swap in since its -2/-2 effect on opposing creatures can wipe out their small mana dorks (Delighted Halfling, Birds of Paradise, Devoted Druid) while buffing your own team, slowing their combo assembly significantly. Trim your slowest top-end (Griselbrand, Wistfulness, Endurance) since this matchup is a race where protection and disruption matter more than raw size. Keep Pact of Negation and Consign to Memory in: Pact of Negation can counter any key spell they cast, while Consign to Memory can counter a triggered ability such as Craterhoof Behemoth's enter trigger, or a colorless spell like Agatha's Soul Cauldron or Walking Ballista.