The state based peanents that double spells seem the most worthwhile, turning our cantrips and spells into powerhouses. We can afford the large one time cost of casting, the instant and sorcery spells that copy are combersome. Also, copies work well with gandalf as they don't cause the cast trigger, outside of arcane bombardment. The enchantments and twinning staff are a slam dunk. The rest is questionable.