How should i continue my ex hunter schooling?

sounds like he just needs more time under saddle, and more time to adjust to the arena. if he responds well, and listens to your cues, just working him more often in areas he's not comfortable in will help him not be so spooky. if he's already a good hunter, then just let him do what he knows how. build on what base he already has, and he'll excel. really need more info to give you much more.