You should be fine because a trip through Temple of Fiends will get you up at least 3 levels if you fight everything there. I remember going through ToF past in WSC version (same as FFO's Normal difficulty) with Knight-Red Wizard-Black Belt-Black Wizard and beating Chaos on level 31 or 32 with auto-aiming disabled (i.e. Ineffective feature activated). You have a White Wizard instead of Red Wizard, so you should be able to beat it thanks to WW's better healing capabilities. Just be patient and use Healing Staves and Healing Helmets a lot during battles.