hey!
I can only comment on adelaide as I havent been to margaret river before. I would take both kites if I was you. we've had some pretty good days here, but also light ones

.
For waves you can go to the midcoast, Middleton, Goolwa, Robe, but yeah most of them are at least a bit down south (Robe is pretty nice though

if you don't mind the drive = about 3hrs).
However, I am not up to the level of wave riding yet so you may find some better suggestions from some of the very keen wave kiters here in SA, so maybe put up a post in the 'SA' section for some more specific replies?
If you are also lovin the flat water stuff, check out North haven on a N/NW er if you lucky, or Port Parham on any S/ SW/W, NW, N direction.
Generally, seabreezes are from the SW here and there are lots of awesome people to meet up with around adelaide!
Cya on the water


cheers, elise