I just wrote out everything to see what weapons are where, how many we have of each type, ect.
If everything is going to equal, (6 assault rifles, 2 in each tier, ect) we need one more tier one Assault rifle, one more SMG for every tier, one more tier one or one more tier 3 sniper, moving around the tier 2's (3 of 'em,) a tier 3 battle rifle, a tier 1 LMG, and a tier 1 and 2 shotgun.
Don't get me wrong, it's your pack, do what you want, this is merely a suggestion.