Focus on + units only, rest gonna be fodder unless you dont want an OP team. I also suggest attach francettes + to Beatrice or any "Premium" units. I hope you know what premium unit is, they "only" appear with plat tickets or nutaku gold. So francette can appear at silver summoning too, so she's dont have high stats like prems do. There will be rank up tickets later on, coming from events or store, dunno the details. With that you can rank up you SR+ beatrice to even UR+ but like i said i dont know the details, maybe we get only SSR rank up ticket but not the UR one.