I highly recommend Red and White.
The White for healing spells, exit, and the rare harm (dia) spells.
Red for extra healing, the rarely needed black magic spell, and the extra physical backup.
With the limited amount of magic casting available in the NES version of this game it's worth more to have a strong physical party, using the Red's black magic ability in the rare occasions where it's worth it such as against undead in the Marsh Cave or Ice Cavern or the Frost Dragons in the Ice Cavern. By mid-game the higher black magic a Red can't learn isn't needed at all.
