I will preface this entire post with one fact. I have an amazingly understanding guild that is made up of mostly r/l friends... This helps alot.

I took my first team into naxx10 with my guild not too long ago. I run druid tank, disc priest, 3x mage. By the end of the instance i had 6 total respecs and a new respect for multiboxing with others.

Started out as trinity group, respec'd once to 5xdps, once back to trinity(holy priest instead of disc), then 5xdps again. 300g worth for respec, never changed glyphs or anything but my druid tank is fully geared boomkin as well for pvp, and my priest is actually much more properly geared for shadow than healing. I run 3x frost mage at all times and that = pretty much unlimited mana for my 5 and I gear accordingly.

Now you may ask why I would respec like that, when your running with a bunch of r/l friends you all do what is necessary to make the run smooth. That for us was a 10 min break for everyone while I respec on 2 toons. This is mainly to combat what puppychow said "Noth (tank on adds, DPS on boss), Gluth (omg), Thaddius (tank thrown diff sides), etc."

Thaddius was not so bad as trinity. The tank punt is solved by simply having a /focus macro for your 2nd tank and refraining from pressing /follow focus.
I did wipe the group once missing the jump between phase 1 & 2. I just happened to jump with my tank forgetting my clones and walking them all off to their demise.
The ± charges sucked for me but we worked out a triangle rotation instead of the typical '2 poles' we'd do with a 10 man group. I formed two of the 3 points on our triangle; One + one -. The other point was a staging area for the rest of the ranged to hold for a second at the start of the pull and during any polarity change so that the lag in me moving polarities hit me only if I was too slow. This makes the fight last a bit longer but mana is never a problem with my team and we still beat the berserk timer by a good 45 seconds (we might outgear naxx10 i'm not sure).
Thaddius is easier as 5xdps in my opinion.

Heigan: what can I say. I hate this fight with PuG's cause they don't listen. I hate this fight as trinity cause I have trouble keeping up after 2 or the phases go by.
The first time I did this fight resulted in a /follow mistake killing all 4 clones but this fight can be done with 2 or 3 people so it just made it alot longer.
5xDPS is much easier on this fight but you still have to pray for low latency or the Safety dance gets risky with /follow lag times. We have yet to make this achievement (all 10 survive) but I have kept all 5 alive one time so far while we lost someone else.
Heigan is easier as 5xdps in my opinion.

Gluth (OMG): This boss can die in a fire for all I care. He's cake as 5x ranged DPS (maybe less cake for 5x shaman I can't say) He is retarded as trinity group.
1) NEVER volunteer for the kiting job. I will buy a coke to the first guy that downs this boss as a 5 box while doing the kiting job.
2) bring AOE. Boomkin, sPriest, 3x mage = more aoe than most groups and it made this fight cake. Plus sPriest 3x frost mage = insane mana recovery after the aoe stages.
3) profit?

We did not full clear yet with all 5 of my toons. We move slow and we ended up at Buffalo Wild Wings drinking beer rather than try the final 3. I'll report If I get them down as a trinity or 5xDPS