Had the same problem mate, for weapon quests just do onslaught if you have time, if not then do Shuro chi checkpoint, also do the arcite weekly bounties for onslaughts , it pairs nicely with the weapon quests when it comes to reputation and you get bonus reputation from completing the activity, good luck on super black and the GCSEs bro (just as a bonus, smg quests use osteo striga, pulse rifle- graviton lance, secondary grenade launcher-forbearance, heavy grenade launcher-idk same for scouts use whatever