5x shaman melt heroics if you know how to earthbind kite the big pulls... When I play just 4 and my g/f plays her mage it's even easier.

SV = 3 badges (40mins or so)
SP = 3 badges (30-45mins)
Ramparts= 3 badges (45min)
Blood Furnace = 3 badges (hour or so)
Sethekk halls = 2 badges (30-40mins)
Mana Tombs = 3 badges (45min)
Botanica = 5 badges (around an hour or so)
Mechanar=3 badges (4 if you do 2nd chick) about an hour or so
Shadow Labs=4 badges (1hr-1hr30min)

These are the ones I have on "farm" status. Others I've tried but haven't got them down to omg easymode badges.




*update slaughtered Mana Tombs today.
**update added in Blood Furnace and destroyed Ikiss.
***update added Shadow Labs and Mech.