One suggestion for a crafted spell if you go bladedancer, use kanna's dance, perfect strike, and any high power spell in a crafted spell after you get your spellcrafting level up.
Best way to double your efficiency in this game. When you get chronomancy and you want to level up a skill, use the timesplit upgrade after you get it and just activate a rest ability and a skill and then use the holding technique for focus.
Setaria, to answer your question, Sublimate provides you with a stable source of Arcana and a max research that can't be removed in exchange for taking away Codices(The second-stage research provider aka Codex).
Has honestly been a lot easier to understand than other games like it. This game is really fun, although I am still trying to figure out if there is a path for a necromancer.