I flew one of these for the first time last weekend. There is an adjustment on the back that adjusts the bow of the spine. It seems that the more bow there is the more stabe and less spinny the kite is but also seems to have less drive.
Is this the case and is there anything else that adjusting the bow will affect?
Nope, that's the purpose. As the wind picks up and the kite gets hard to handle, more bow will calm it down. Bridle adjustment is also doable, but touchy. Angle of attack, like any kite, pull, lift, spin, etc.