General rule of thumb I go by is doing it in waves. Everything level 30 first. Then level 50 to CC then 20. Last step is have core team all 50CC50 with no iron/bronze units main team. But keep a couple of bronze min cost L40 soldiers because they are handy to sub in for some maps. After that you max level golds, plats, blacks for awakening and level handy niche units you can sub in.

With the revivals going so fast right now you need to get on them to pick up some nice plats/silvers. But you need a team that can handle at least the first 2-3 maps each day.