Bow with defouled weapon.
I tested in Cyrodiil multiple times.
The Focused Aim + Mark Target + Covenant Bow set = BEtter Damage and range.
Just a side note, its not mentioned in the tool tip, but Lethal Arrow ignores armor, Focused Aim doesn't.
I convinced a friend to switch morphs and they went from 1.8-1.9k damage to 2.1-2.2k damage with Lethal Arrow.
Focused Aim is better for range, and appears better on paper, but Lethal Arrow edges it out slightly overall due to its penetration value.
Unless they have patched it, last time I checked, Lethal Arrow ignores armor and Focused Aim didn't last time I checked.