a) you can never have too many kites ----- true
b) parksy is spot on
c) i'm 82kg and have a 14m
When i was learning i found cabrinha switchblades were great as they are stable as, great wind range and good boost with decent depower I had a 10m and 7m which i could get out on in 16kts cos they have great low end.
You need to try them really bud. A 10 is a good shout though