Too add, on the character plates only use them if you see something worth while, dont say hey I don't have that ninja.
I'm assuming you're f2p, so look at all your resources as an investment and how it will affect you in the long run. Do you see yourself using this ninja VERY often down the road in ranked or your team? If not pass on the event and save. While I love collecting ninjas, and I want to keep pulling for Ay, I need to bite my tounge and hold out and save my seals for roshi and GNW treasures, why? Cause I will be using them down the line, when they come out and are FARRRR more utilizable then Ay will be at that point. Make smart choices where you spent any time of resource in this game to benefit you in the long run.