N'Zoth LFR - got my 8-stack key last night!

Signed up for Waking Dream LFR as tank last night, arrived at N'Zoth and a bunch of skeletons, team had seven stacks of determination, and the tank asking "hey you know the fight?", I said "yeah, you want me up or down", he said "good, you go down", he said 1-3-5 down and he readychecked, off we go, fight begins, boop boop boop, portal opens, we go down, kill psychus, come back up and everybody is dead, now the group is on 8 stacks of determination and I know from personal experience that people get pretty punch at 8 stacks. Tank logs off and I'm made raid leader of this fight for the first time.Waiting for a new tank to arrive, a couple of people admitted to being completely unfamiliar with the fight and somebody suggested googling up a YouTube video on the fight while we were waiting, at least so they could see how challenging it is going to be.I took a look at the group composition, and bottom side had four healers in it, topside only one, and the bottom side group had a lot of melee. I figured the bottom side was more damage intense and more people were going down, so 3 healers down, two healers up. I also reasoned that there was way more things to accidentally stand in down below, so I assigned the hunters to the bottom group, and favored melee up top. Other than that, I didn't change much, and I kept the groups 1-3-5.That's when the other tank arrived.I whispered, "Hi, we're both recently arrived" (padding my ego, those weren't all my wipes!) "do you know the fight?"He replies, "12-12H baby".So, yeah...He whispers "give me bottom, don't taunt".I mentally hand him the leadership baton, and my brain has switched to student mode, ready to learn from somebody who's gone through this a time or two on hard-mode.Somebody who's been there the whole time calls out "1-3-5 bottom", I /readycheck, he clicks not ready, he /rw's WAIT and the mages and warlocks all start complaining while everybody else starts whipping out their toys.Time to watch and learn.He massively changes the groups around. I don't know his reasoning, unfortunately, and I didn't check the composition when he was done. But he did it quick and he seemed happy with his choices, he didn't ask anybody any questions, he just did it.Now, he does something very important to new raiders - he moves over about 20 yards, with the blue chicklet on his head, and types/rw groups 2,4 stack on blueA couple players stack on blue.The rest of the raid goes huh?He types it again/rw groups 2,4 stack on blueA few more players move over.And now I'm starting to get it - he can tell which groups have moved by the distance indicator on the player's tile.He types it again/rw groups 2,4 stack on blueThe rest of groups 2,4 move over, and now we're standing as two groups and it's obvious that we know which group is which.Now he types/rw groups 1,3,5 stack on blue, 2,4 stack on yellow(Yellow was my marker)The raid moves to their new positions perfectly.Nobody is talking.Nobody is complaining.I cry a little.He readychecks.We all click ready instantly.We separate from our bodies.​We execute perfectly as a team for five beautiful minutes, in phase 1 nobody gets mind controlled, in phase 2 during mind grasp he does /rw STACK ON BLUE and we go find him so nobody has to think, nobody gets thwacked by the big tentacle because the he isn't worried about me choosing wrong, he just goes to the far tentacle, the proper groups stay up, the proper groups go down, necklaces get clicked (/rw CLICK NECKLACE), nobody gets dragged into N'Zoth or off the edge, every time I look at my minimap I see 25 player-circles in a tight cluster.I feel a big goofy smile on my face as I'm feeling that magical moment where 25 strangers start to act as one giant boss-killing factory.Phase three begins.I've never lost at phase three, but my successes mean I've also never deeply learned the mechanics and our 10-determination historically got us through it, but fear not, our 12-12H tank has things well in hand.The thought harvester appears - Psychus's little brother.Tank taunts the thought harvester. The large blue ring appears around the thought harvester.Players scatter away from the large blue ring./rw STACK ON BLUEWe stack on blue. The ring goes away and I still have 95 sanity.OooooohhhhThe raid is still stacked tight. Countdown timers appear above our heads.321/rw STACK ON BLUE(He's already moved to the right)We drop our puddles in a small area, and we move over to the clean ground he's standing on.OoooooohhhhhI literally squeal, I'm having so much fun!Nobody is dead. Pew-pews are flying at N'Zoth as his health is melting. Now it's rinse-repeat the same mechanics a couple times and we get better and better at it. Victory is already achieved in our minds, the scoreboard just needs to be updated.N'Zoth dies. A bunch of people in the group get their achieves for killing him for the first time.We return to MOTHER.Somebody says "LET'S DO IT AGAIN!" At 8 stacks of determination, yes, somebody wants to do that magical thing we did again.I don't know how to say it any simpler for those that have never played the game - I find those moments are the best of WoW.Thanks for helping us, "12/12H" tank, we LFR'ers learned something! Technically we only needed to learn one new-but-essential skill - stack on blue - before the fight even began. He forced us to convince him that we could follow that instruction before he began. That one extra skill made all the difference in this fight, giving an experienced tank the ability to steer the flow of his team of rookies in the right direction.I've now done N'Zoth with 10 stacks, 9 stacks twice, and now 8 stacks. Hopefully I can applied what I learned to help the team get a completion with seven stacks or less in the future!