Carryovers are optional in the first zone and are more essential in the second and third zones. If you're able to carryover lvl2 without sacrificing too much time, it's generally worth. Lvl1...maybe.

Boss can be kill 1 cycle earlier if I got better positioning leading into my first lvl2 deathblow or if I possibly got lvl1 after using the lvl3.

Juju: Mithril Garment, Spirit Ring, Might Ring, Shining Material

Leon: Silver Garment, Battle Bracelet

Vitis: Silver Garment, Strength Bracelet