What kind of range do you need to solo bosses?

and i might be wrong about "being unable without crit chance" but getting the items is so incredibly boring for me, i like to remain sitting and do nothing.

Is the requirement 10 of each mask + 1 of each boss drop, or do you need to down the actual bosses? The masks drop way more often now, I probably have 100 of each from doing various "kill 300" quests with a pet looting.