Most of the time the winds are from 12 to 18 kt(low season),high season(3 months) 15 to 25kt.As I tested only two times,I tried to read some reviews on the net,but just find few reviwes about this kite,if don't mind give your opinion....
I would go 9 and 12 and maybe 14 if you ride a TT in 12 to 18 often.
One of my friend which is a really good kiter that's been on Bandit from the B1 rides 9 and 14 B5 at 75 kg. He rides both TT and surf.
I weigh 77kg and will be riding a 3 kite quiver of 9-12 and 14 B6. Havent tried the 12 m yet but I have tried the 9m and 14m.
I tried the 14m in really light wind 10-12 knots (not much fun on a TT), in 12 to 18 you will have agreat time though.
I tried the 9m last week in winds ranging from 25 to 32-33 knots and it was a blast. That kite has a lot of lift and it boost really high, it feels very stable in gusty wind and you can dump a lot of power really fast.
I also learned kitesurfing on waroos 9m and 13m 2008. If you go 9 and 14 you will have about the same wind range even though the kites are totally different.