tri-boxing

[kelika2]

Alright, I am going to skip my resume and anecdotes about why I do it, but I do it.  I know about the 1500 player thing as well.

So, right now sometimes I dualbox through a task force with a bot/trap mastermind.  defense, -regen, etc.

but I want to start doing it with a third box and not sure what mastermind to do it with and torn between a few combos:

 

ninja/time.  mostly passive, lots of stacking defense/-tohit, able to autofollow without much action needed

thug/cold.  rebubble every 2 minutes and forget it most of the time.  has some -regen like the bot/traps

mercs/traps to why not keep it ranged and more bubbles

 

either way im thinking of defense based fire-and-forget autofollow alts

[Maelwys]

FF is the defacto "Fire and Forget" Defence-buffing follower - just click 3-4 buttons every ~4 minutes (Power Boost and the two Bubbles; plus *potentially* Radial Clarion) and you're instantly softcapped. But it's much less attractive if you already have a /Traps tagging along; even if the FFG is squishy and slow.

Time and Cold definitely work too - Time needs button clicks a bit more often but can be Powerboosted.
Both of those sets have decent on-demand active buffs/debuffs available for when you find yourself up against AVs.
Another option that you may not have considered is a Dark Affinity Controller - Fade whilst not Power Boostable can be Perma'd with a bit of effort; and the rest of its toolset compares favourably. Taking Illusion primary synergises nicely here as the +Recharge you build for Fade will provide better uptime on Phantom Army.

However if you tend to run at level 50 then I'd rather bring a VEAT Crab/Fortuna than any of the above... and if you tend to run a lot of lower-level TFs (which don't benefit as much from all the overpowered set bonuses and IO fluff) and play a variety of ATs on your "main" account then it may be worth bringing a Shield Defence Tanker along instead.

Crabbermind and Fortuna VEATs both bring a *lot* of  damage output, strong +Damage/ToHit buffs and +Defence (via Maneuvers or Mind Link) plus debuffs or CC (Venom Grenade or Psychic Wail/Aura of Confusion) but they're best with oodles of Global Recharge so if you're exemplaring for a lot of lowbie TFs they'll suffer.
+ Crabbermind pets are squishy and will die pretty often whilst farming at +4x8, but they need zero micromanaging and are excellent help at taking down an AV. The Crab themselves can just set Frenzy or Dark Obliteration on Auto and trigger their self-heal occasionally - plenty of room to take double Leadership powers.

+ Fortunas are less tough than Crabs, but they're still Defence-capped with damage resistance that scales up as their health drops. Confusing nasty Bosses/AVs is always fun; and Psychic Wail makes an excellent Crowd-Clearer. The downside is that Mind Link is rather difficult to perma on a Fort; especially if you're exemplaring.

Tankerwise, for an autofollowing helper it'll be hard to beat Superstrength (with Footstomp on Auto) as a secondary. There are lots of primaries that work at lower levels; but Shield Defence will buff teammates a fair bit even without the Leadership pool due to "Grant Cover".

- - - - - - - - - -

All that said... if you're already at or near the Defence Softcap (not unlikely with /Traps) and you're set on a MM then don't overlook Thermal.

Thermals are to +Resistance what Cold is to +Defence; and they bring Healing that /Traps lacks. So this would probably be the best all rounder IMO - Bubble up once every 4 minutes, stick "Warmth" on Autofire, and save "Melt Armor" and "Heat Exhaustion" for bosses/AVs. As for the AT? Another Mastermind would provide extra passive damage output; or an Earth Controller would give you something to Tank AVs for you (Stoney Taunts and can hit the Resistance cap to everything with Thermal buffs and the Aura IOs).

I have some very fond memories from Live dualboxing an Earth/Thermal Controller with a Robotics/Traps Mastermind. 
 

Edited July 11 by Maelwys

[kelika2]

I think I was over-thinking it.

two thug/cold masterminds

their maneuvers + ice shields + two fogs + 2 player maneuvers

 

enforcer has low level aoe, then arsonist comes along and gravy from there.  because of the stacking defense i can main a blaster and have the masterminds auto follow

[SeraphimKensai]

I have two necro/darks I like to run together, been contemplating making a third. Otherwise I have 4 bots MMs but only three accounts so usually a bots/time, bots/elec, and bots/kin. I usually main the elec and alt tab to the others as necessary.

[Hedgefund]

One oddball 3rd box I was moderately surprised by its effectiveness was an ice/poison controller.  It does a heckuva job just sitting standing there with Arctic Air and Venomous Gas.  Put Envenom on auto if you want, certainly useful for the AV fights.  I don't have dedicated 3-box teams by any means, but if I need a notice I'll bring out my Trap MM to go along with it and on a whim I added the ice/poison and was really pleased by the results.