So (and I don't really know the SPG scheme that well so please corrct where I am wrong...but I am always interested to see if there is a good deal going and so like to understand things..)
$1000 AMEX points = 333 SPG Points (???)
The Bora Bora Hotel..if I have the right one cost 20,000 to 30,000 points to redeem per night (i am also assuming that they ONLY have overwater rooms and so they will not give youa land room...)
This is then say then 60,000 to 90,000 AMEX points
Which at an earn rate of 1.5 is $AUS40,000 to $60,000 spend per night.
Now if I have the right hotel in either the St Regis or Le Meridien the rack night rate is about 72000 to 78000 XPF with the echange rate being about 87 /$US =say $900 US per night.
Which is say an earn of about 2 per cent. Which is say better than flight redemtion to Thailand , but not as good asa RTW redemption.
However
if you have to spend $195 AUS membership fee per year...you would need to take this into account (I currently just keep taking up free cards....with point bonuses if I can get them).
Without the yearly fee the redemption is a healthy one.....but pay too many $195 and it becomes less so...
PS..though I fully understand the allure of your targetted reward....beautiful views