When hunting Hoo Mjuu keep a couple things in mind. There is from 1 hr to 2 hrs spawn time.(common knowledge)

There are several spawn points (common knowledge)

He spawns exactly 8 minutes after a mendicant or piper(in my experience)

The only spawn area I have ever got the signa to drop is in the back right corner.(in my experience)

The "real" Hoo Mjuu when in battle, will wait till about 1/8th inch life left before he uses benediction. Real meaning the one that drops the Monster Signa.

Finally, Hoo Mjuu will spawn 1-2 spawn groups after the first piper spawns.(in my experience) Meaning only persecuters and mendicants will spawn until Hoo Mjuu is comming.

Every 8 minutes or so there will be approx 4-5 spawns in the Hoo Mjuu area, persecuters, mendicants, bees, and pipers. This is what I mean by spawn group.

So instead of spamming macros for an hour straight you can take a 4-6 minute break between spawn groups. Use the /targetnpc macro. They put a wait time on bieng able to provoke after targeting so try to attack with a low delay weapon, or maybe spells.

Good Luck