Number of pack depends only on where you place on Saturday.

As for the quarterfinal match ups, lol ..... I took screenshots of all group stuff for over 2 months and tried to figure out, it's NOT by points/power/activity/group level/members/fields won/previous weeks placements, so i am 99% sure it's just random. I did notice that a lot of time we got first match on Sat with one of 2 groups we fought on Wed, but that could be just randomness still since i only had like 10 sample size.