Alright, after playing with different "surf" boards on the water that seems to be true, more than 6' feels just too big for kite wavering...
I'm still fuzzy about thrusters' side fins angle (not parallel to the central one).
It seems to create a drag and slow down the board. Majority of kite surfboards have this fin configuration as well.
What's the purpose of this?
Are there surf kiteboards with all-parallel fins?