farming Fg effectively requires knowing your opponents, like when to quit if you dont have an early lobotomizer, or when to not play it if youre better off saving quanta for miracles, or if its going to get stolen and used against you. Also switching from dragons to angels has been more effective for me, and having upgraded towers made a huge difference. You might be better off grinding ai3 or bronze arenas until you can afford to upgrade more than just the rays.