This staff brings me to 301 Enhancing Magic (without merits):
256 under Light Arts
+15 Scholar's Pants
+7 Argute Gown
+7 Enhancing Torque
+5 Merciful Cape
+3 Augmenting Earring
The only other +Enhancing piece available to SCH is from an ACP key, +3 max on a belt. That's 20 damage for enspells and 28 damage reduction in Phalanx.
The rest of the mods are junk. Elemental Staves will give more accuracy than this in addition to their hidden effect damage boost. Would have liked Fast Cast on there as well, but I'm perfectly happy with this staff.