When going in it's better to expect nothing so you don't get sad but will get happy if you get something.
Not sure how much boxes I have opened, rolled like 150-200 times though and mainly gotten level 4 magatamas which are nice
I'm still under the assumption that it's rigged, but that's just an assumption. It's still a good event because you get a lot of stuff, but the lucky box are something I don't trust and will never trust considering the events that happened recently so it's better to focus on getting everything, except ninjas of rare or super rare value from the lucky box, that lucky board has to offer.