First off, welcome to Dual-Boxing.com

I personally prefer a blacklist of things to not pass, to a whitelist which will only pass certain things.
With a blacklist I got by quite well by not passing F1, Tab and NumLock.

Ultimately you add as many keys or combinations to either list as you'd like.
In my case, I use a ton of hotkeys and find not passing a smaller number of keys easier then configuring a much larger number of keys in which to pass.
Playing 5x of the same class can greatly alleviate this.
But I would think you'll want more hotkeys with even two classes, or especially so with a tank + healer + 3x dps.

Hunters are a little easier then melee, but a little harder then casters.
They will automatically switch to melee swings if an enemy closes to melee range.
Once you take a melee swing, follow is broken.
Jamba has an option for strobe following, but strobe makes it quite hard to position toons.

Definitely grab the addon Jamba.
It makes so many boxing things much easier.

Look towards putting some spells on round robin.
For example, you can make Concussive Shot on a round-robin.
Make macro's like this...

Hunter 1
#show Concussive Shot
/Assist [target=focus]
/castsequence reset=20 Concussive Shot,,,,

Hunter 2
#show Concussive Shot
/Assist [target=focus]
/castsequence reset=20 ,Concussive Shot,,,

Just move the comma's down for each Hunter.
On the first click Hunter 1 casts, and the others are on comma's (no action).
Etc...

For your dps, I'd really look into "Click Castsequences".
There are a lot of them floating around, and they greatly increase your DPS when boxing.