For KZN coast the Mullers may be a better option. It tacks well and if you have strong oblique winds you can get a bait in....... Strong offshore winds then go with the regular fishing kite.
Windsong or http://radicalkites.co.za/4-home, both the same kite but Radical now handles the sales and their service is perfect.
I would advise that a Kite fishing setup consists of a light wind kite, a extreme tacking kite (mullers) and a storm wind kite. The same as you would have a scratching setup a surf setup and a heavy setup, there is no ONE solution fits ALL.