Thanks for the shout out Matt!
The other thing to consider is that the rider will generally move forward on the board when the foil is moved forward.
To fly straight the force of gravity acting on the whole system needs to be equal to the lift generated by the foil, and the effective summed location of the COGs of the rider + board + foil must be directly above the effective centre of lift. By effective I mean taking into account the moment generated by the stab so your picture can be representative assuming different stabilizer shimming.