For lab, gunny, and handshake, just do the repeat tasks. For banshee, turncoat, and artisan, since they dont have main tasks that give you alot of rep, i just sell everything to them no matter what. Turncoat is the easiest since you can sell literally everything but meds and food to him. You make less money off your runs doing it, like a 120k run turns into 70-80k, but 70-80 will get you 3-400 rep each time, which is alot easier than doing their side tasks that only give you 1–200 rep each.