Andy, I would start off using beak hooks to start with, then after you get your style right, go to circle then.
I personally like the black magic K/S hooks, yeah they rust, but they are cheep and are perfect for the job. 4/0 for small yems up to about 6/0.
Arapanui has quite a few kings, esk has allot but most are very small. Awatoto also has quite a few, I would walk in from the ferry road end though, less rods. If you are serious about it, go to mohaka when you get a flat sea, awsome kingfish there, just wicked fishing.