I ride an Armstrong foil setup with a 100cm mast for kite foiling, with HA 725 front wing and HA 195 tail wing. This setup absolutely rips kiting if you are an advanced kite foiler. The 60cm fuselage is a good mix of stability and turning. You could go with the 70cm fuselage if you are new to foiling. The 50cm fuselage is good for tighter turns but less stable. 50cm fuselage would be good for surfing or winging if you are experienced or looking for sharp turns and best maneuverability. Overall the 60cm is good for almost everything and works well for me while kiting at high speeds as an advanced rider.