Needs to be in Jan really to ensure that you get sufficient local boat numbers. This is the traditional holiday time and you do need a strong local fleet presence to make it viable.

Any other GC can't be 6 to 8 months before/after the Australian GC. Reason is logistics and costs. Events too close to each other means that people will only choose one. 18 month gap seems to work for the A-Cats between events when Aus/NZ host a worlds.