Regarding equipment I have seen used in Canberra it seems that competent sailors on 130 to 160 litre boards use around 8.5m sails for the moderate summer breezes and often hang onto these into fresh winds - so that should give you an idea for the future. Stiff easterly 'sea' breezes when they arrive (late on a summer's day) can be lots of fun too.
Winds are gusty in summer in Canberra (or any time really which is why Canberra produces more than its fair share of top tactical dingy racers) as they bend around the mountains and react to the thermal mass of the continent causing significant shifts. With the prevailing NW winds they will shift westerly in gusts and back up to North in the lulls - you need to play their game when pointing or doing tacks/ gybes.
Gusty conditions certainly put a premium on having a good match with the rig components, the board, straps, fin, harness & lines. The waist harness is popular and user friendly, while some speed merchants with free race gear will swear by the seat harness.
The fresh to strong wind 'season' is spring when 7m is a popular size. Keen slalom types will have a smaller sail in their quiver for when things get really interesting. One question is whether to rig for the gusts or the lulls. Southerly winds in winter can be relatively gust free, but a bit cool, the days are short and gear stays soggy (small price to pay though).
Although there is no WS club in Canberra, there is a strong local WS community that is more than willing to share experiences - just ask around at your local beach.