a 10/8m combo would do the trick for WA for your weight. If you have good skills, you may even get away with 9/7 depending on the wind range you are looking for.
The beauty of the Ozone kites in general (including the C4) is that their foil profile is designed to produce good dynamic power ie sining the kite produces good apparent wind power.
A Skilled pilot will be able to ride fast and sine the kite to produce all the power you need. When you stomp it and bust a trick, the instant resistance punches the kite further upwind which drops the power momentarily making freestyle easier to throw down.
The lower static power and higher apparent wind power in the Ozones makes it possible to ride slower with a good edge to keep the kite easily and comfortably under control when over powered and to create the power you need when under powered, this gives them a massive 15 knot useable wind range in the hands of someone who knows what they are doing.
Team rider Abel mostly rides the 9 and 7m even when others are on much bigger gruntier kites because he rides fast and understands apparent wind power. This is why I suggested 9 and 7. If you are less experienced, go with up to 11 and 8m Like Skinner says.
Restraint!? Nah, once you get used to C4s they're all you'll want to ride. So if you start with a 9 be prepared to add a 7 and a 12 in the near future. Or just start straight up with the 8-11 combo. Either way you'll be stoked.