My 2 cts;
Me: 72kg, Nobile Zen Freeride, Soul 6, 10 and 12m. (sharing with my son)
Wind 6 - 10 kts G12kts : 12m. super combo in the sub 10kts and really able to loose the power in the gusts and very stable in the gusts, if this kite stays in the air you can foil. My son on the beach..
Wind 8 - 12 kts G15kts : 10m. the perfect setup, jumps are great (i prefer -3m lines but my son not on the TT), more lively in gusty conditions, keep it more in the window in gusty wind. My son on the 12 (with Skim & TT) and me on the 10, perfect.The money kite if you want to boost on a TT in 20+ kts, from 15 kts and a TT: Big smile..
Wind 15 - 20 kts G?? : 6m. with -3m shorter lines. great in waves nice drift in the kite. My son on the 10m boosting and in the upper wind range wanting my 6m... (and I have to take a 5m tube)