Although the economizer is useful, it's not nesecary at all. I got through the final battle casting all the ultimas and cure3s (because I forgot that I had megalixers...) that I wanted without even having to think about tinctures. My Terra had a gem box +a gold hairpin, Celes had an offering and a Genji Glove and I had Gogo mimic Terra while my Sabin used bum rush and cured.