Normally weight and skill are usefull additions for best answer.
At 75 KGs a 9m and a 13m on a 136 TT

Add a surf board and down winder and U can get going in fairly light conditions.
When I add another kite it will likely be a 15-17m ie a bigger board can't compensate for light wind performance these offer.
Obviously we get storms and if U like 30+knots U go smaller - but these are not that common.

Here is BOM reference -
reg.bom.gov.au/climate/averages/wind/selection_map.shtml
Use 3pm settings as reflects sea breeze influence.

Cheers Rick

Most of the last summer has been Around the 12-18 knots range with average gusts coming in around 3 or 4 knots higher.
Last 3 weeks have been very inconsistent with rain squalls making it harder to find constant wind and some periods recording 18, 28(with a 45 gust) and then 6knots over a 12 min period.

I usually use the Maroochydore Airport (only about 500m from the beach) Live wind readings on this site before putting my kite in the car and driving the 10 mins to the beach.

62kgs and rode a 10m all summer (134 tt)

Hope this helps

Is there a station or app for lake weyba. Or do you just use this site and take a few knots off as its over the dunes???