Muri is great........and you're right about Aitutaki....its far better, quieter, bigger than the 'main' island of Raro.......
Aitutaki has the greatest sandbars and beautiful clear, flat water ...if the wind is on its heaven!
Some of the sailing destinations & info on www.kiteboardaitutaki.com..
went with them last year, they had a boat organised to the motu...its essential and they have another trip in August with some space....
Cop this!