>>533773175
V0R0 is fine
V1R0 streamlines her rotation.
If you going for damage, biggest jumps are V3 and V6.

>>532464638
I am pretty sure that a V0 Niketta will out-damage Sabrina no matter what.
I am too lazy to convert the tables, but the format is similar to >>532458889 Top table is Niketta, bottom table is Tololo. Last 2 columns on the Tololo table are for V6 Klukai with and without Mechty. Second column on the Tololo table, is Tololo's damage at V0 without supports. Both tables assume they are on Springfield's V1 buff.

>>528513751
Those damage numbers have the Def Down debuff included. See pic related. See how the damage numbers for the first column are the same? That is because the first column are numbers for a V0 Qiongjiu with Golden Melody. Sixth row says the guide maker used 3804 for the enemy's debuff and that the 30% def down has been accounted for. Springfield's active heals also scale off attack, and you usually want her heals to be as big as possible since some of the overflow gets converted to more Hydo damage for V1.