... more kites the merrier.

Depends on a heap of factors but in my opinion get 10 and 7m.
Read somewhere here that the 9m is different to all the other sizes in that it is not tuned to go faster or slower but a feel all of its own. 14m to 10m made a little quicker, 8 to 5 made a little slower or rather easier and not so punchy in gusts so the only odd one out is 9m. What it actually feels like is a mystery til guys test it.
Anyway, just one opinion, take with a grain of salt!
cheers,
Robbie