Keep in mind that freestylers use tiny fins - 19 cm is considered big for the guys. Small fins require a more upright stance and tons of mastfoot pressure. Freestyle sails have a tighter leech and higher COE to enable that (which is also why they can work quite well for windfoiling).
Another reason to have the mast foot close to the front strap is to allow for faster rotations. The more the mast foot is back, the easier it is to rotate the board in the air.
Neither the small fin nor the fast air rotation applies to your 120Xcite, I assume

. But experimenting is good - maybe there's some other benefit.