The benefits of a Range's holster is you have plenty of space to bring additional Lost Actions such as Lost Shell II and Protect II, or Resistance Reraiser.

Pre-Entry holster allows you to free up capacity for fights from Boss #3 and beyond.

Being an MP Ranged is beneficial for mainly Healers on DPS Lost Actions, Casters using Font of Magic and Dark Knight using Edge of Shadow and Flood of Shadow. MP Refresh does not work on a BLM, unfortunately.

The advantage of this you can bring along Lost Shell II, more Resistance Reraiser since your holster is not filled to the brim.

For a Boss #3 holster, remove the Pure Essence and use an entry holster

Since Lost Slash potency triples when it lands a critical hit, MCH Reassemble grants the next skill to be critical. Rejoice! If you're a MCH because this holster could be for you, if you like.

Lost Slash is obtained from the Forgotten Fragment of Violence, found in Zone 3 Star Rank monsters and Ashkins of Bozja Southern Front.

For a Boss #3 holster, remove the Pure Essence and use an entry holster.