Can one sleep when putting his head on a Shtender during Rosh Hashana afternoon, when it says one should not sleep?

Although the Arizal is lenient and permits sleeping in that afternoon, other Poskim are stringent such as the Mate Ephraim (598: 1), who claims that we cannot compare ourselves to the Arizal, who would reach the greatest spiritual heights in his sleep, way over what others can even dream about when they are awake. Nevertheless many Poskim are lenient when sleep is needed, as the Mishna Berura who also quotes the Arizal. (See also, Shulchan Aruch Horav – ibid. 8, Sidur Yaavetz 9, Kitzur Shulchan Aruch 129: 20, Aruch Hashulchan ibid. 4, and others). Horav Shlomo Miller’s Shlit’a opinion is similar.