I've tried:
Code
<if type="*Magic"> <equip when="precast" set="Fastcastset" /> <if Spell="Shantotto|Naji|Kupipi|Excenmille|Ayame|Nanna Mihgo|Curilla|Volker|Ajido-Marujido|Trion|Zeid|Lion|Tenzen|Mihli Aliapoh|Valaineral|Joachim|Naja Salaheem|Prishe|Ulmia|Cherukiki|Iron Eater|Gadalar|Lehko Habhoka|Zazarg|Ovjang|Mnejing|Sakura|Luzaf"> <equip when="midcast" set="Trust Set" /> </if> </if>
and:
Code
<if type="*Magic"> <equip when="precast" set="Fastcastset" /> <if Skill="TrustMagic"> <equip when="midcast" set="Trust Set" /> </if> </if>
I assume the reason this one doesn't work is because there isn't an actual TrustMagic skill.