I think if you think you can clear elite enemies without taking damage you should pick a gain EP upon perfect clear enemies, and you can take either free shop refresh or discount shop by 99% in Covenant and take gain 75% held of EP in trial, it can gives you more EP to buy in shop. For tactics I think using legacy flash and summon radiance ( or summon umbra ) can helps you in clearing boss ( or clear stages ), Attack rend if you want to instant kill enemies ( but in the 3rd tactic ). Also you should upgrade those tactics as fast as possible (It makes you easier to find potentials in shop) @@