My npc has been 65 for months so i don't bother killing mobs anymore for the tactics pearl quest, i go right for the ??? target. However one trick i found out is that for npc xp the level of mobs doesn't matter, just the number of mobs. The stray mobs created by the receptacle can be killed in 1 or 2 swings and are best for this. You can quickly and safely max your npc xp killing up to 30 of these fast (you might need to attack the receptactle every now and then to make it produce strays faster). That will give you 1500 xp really fast, then the difference between the floors is only about 200-250 more per floor, which is like less than 1 kill when you xp npc. Of course maybe you go up floors for fun with your friends or for normal xp on yourself, but this is an alternative to save you time.
npc tactics xp
However one trick i found out is that for npc xp the level of mobs doesn't matter, just the number of mobs. The stray mobs created by the receptacle can be killed in 1 or 2 swings and are best for this. You can quickly and safely max your npc xp killing up to 30 of these fast (you might need to attack the receptactle every now and then to make it produce strays faster). That will give you 1500 xp really fast, then the difference between the floors is only about 200-250 more per floor, which is like less than 1 kill when you xp npc.
Of course maybe you go up floors for fun with your friends or for normal xp on yourself, but this is an alternative to save you time.