Q. Due to the length of the davening during Rosh Hashana, the time needed for a seuda with family and guest and the long walk to the water source, is it possible to recite Tashlich immediately after Musaf or even better at night after the seuda?
A. Mishna Berura (583: 8) mentions that one should recite Tashlich after Mincha before sunset. However, Mate Ephraim (598: 7) opines that it can be said before Mincha and even at night. (See Kovetz Halochos 20: 9).
Horav Shlomo Miller's Shlit'a opinion is similar.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit'a.