Assuming the achievements are DLC specific & we will have a DLC playlist, probably 12 players;
could probably knock out majority of achievements in one or two games with a group of 3-4 people using guests.
The less boosting matches required, the less chance for xp ban.
I'll check back release day for others who can join up with guests.
nayr2012 (+3 guests)
I took a stroll, and spied a maid,
but Matron's duty stayed my blade.
So busy now, I miss the thrill,
if only I had time to kill.