I think you are on a winner here.
It is becoming well known that the best wind in Australia outside the summer seabreeze season is the trade wind belt along the north queensland coast, and through to the hula coast of PNG.
Torres Straits are even windier than Lizard Island, which is already a pretty wind blown place.
There is a big market of kiters from the southern states that are starved for wind from April to September, the issue is finding blue water locations they can visit. Lizard is expensive and the camping facilities primitive. Cooktown is muddy coastal waters with crocs. Outer GBR locations are great but require liveaboard boat support. Poruma looks excellent in offering accommodation right at the location.
Regarding what flat water kiters are after, the ideal situation is a low flat island aligned perpendicular to the wind. Poruma itself isn't too bad, but the angle is not perfect and the island, if it has houses and trees on it, might make a bit too much turbulence.
However...looking at google earth, there is a very promising flat cay - island to the north east, just over 8km away (9 59.200'S 143 07.150'E). See pic below.
With boat support, this looks very promising!
Some info on the tidal range would also be useful for kiters; eg what tidal height does the reef flat become exposed?
Good luck with it. send me an email if you would like more info on setting up the ecotourism side of things....
andy@reefecotours.com www.reefecotours.com
Andy