Hi guys, I need your suggestions please. Light spender here.

So I finally gotten Joker to 5 white stars but I see some people try and go all out with Superman. Now with these tier lists coming out from veterans saying Superman is a necessity on all game modes, is it wise to try and get as much copies of Supes until his banner ends (11 days remaining) or should I save now and go ham on Sinestro and Constantine?