During the repetition of the Amidah for both days of Rosh Hashanah, most Ashkenazi communities recite piyutim entitled ה׳ מלך. On the first day, the format is relatively simple, being arranged in a regular alphabetical acrostic (with three verses for ת, due to the threefold nature of the refrain). However, on the second day, a more complex acrostic structure exists, although I am not quite sure how to view it. Furthermore, the third line of each stanza begins with the words "אילו ואילו," "These and Those."
My question here is twofold:
What is the purpose for the more complex (and frankly baffling) acrostic structure?
What is the rationale for using אילו ואילו? Is it supposed to be a reference to the Talmudic principle?