If it's only your second season instructing, your best chance of getting a job down here would be to get a working holiday visa, then come a do a hiring clinic, it's kind of like a skiing interview, it's a bit risky, as you may not get the job, but worst case scenario you'd just have to get another job doing something else.
Cardrona probably has the highest percentage of park instructors (apart from Snowpark, which isn't really a proper ski school), but the easiest ski school out the Qtown/Wanaka resorts (ie the good ones) to get a job in is probably Treble Cone.
If you don't fancy risking the casual hire, get your level 3 and try and meet a supervisor who works down here, that seems the only guaranteed way of doing it, a bunch of my friends who have their level 3 didn't get jobs here this year applying the normal way.