RE: Smallest sail on a carve 162
The carve 162 is a racer man, you may want to stich with the bigger sails, especially considering your weight. But your miniul wind will limit itself to a maximum of 6 bft with a board like that. But if you hit those conditions with a 162 on flat water i recommend not going under the 6.1 minimum they give on the website. 5.7 really is small for a board like that, even if you put the smalles recommended fin on the board. U can go like 2 cm under the recommended but anything over that will get your board out of balance.
however i agree with the precvious, the 7.0 will do fine if you're hitting 5.5 BFt (considering your weight).
Experience is what thought me, and i mean, the best teacher is always you!
Haiko, aka Crazychemical