Helping a friend in coop through the story, need help on gear to not he op while playing with him /u/Masterwork_Core Monster Hunter: World

He just reached High rank yesterday (finished the everstream zora quest) and I am using the switch axe for now (bone axe at rarity 5 i think?) and I adjusted my whole gear so that I follow his gear and not destroy everything with my fatalis set lol

my question is what rarity should I go to during high rank so that I stay around the expected levels for the content?

He just reached High rank yesterday (finished the everstream zora quest) and I am using the switch axe for now (bone axe at rarity 5 i think?) and I adjusted my whole gear so that I follow his gear and not destroy everything with my fatalis set lol

my question is what rarity should I go to during high rank so that I stay around the expected levels for the content?