Psalm 18 has a very complex structure, consisting either several nested menorahs (heptamerous chiasms), or one large menorah with other structural elements sprinkled in.
When pointing and arranging this antiphonal version, I based it off of the single large menorah found in the psalm. Rather than use a separate tone for each level (although this is preferable), I used only two distinct tones, as this is easier to sing (for now).
Section A begins with one tone, then B and C are a different tone. D is the crest or center of the menorah, and its tone is the same found in A. D is also very short, and the rest of the psalm works its way back through the B’ and C’ tones, and finally back to the A’ tone.
Due to its length, we will be singing this in three or four parts, so the entire structure may not be immediately obvious to someone who isn’t paying close attention.