in a vertical upline... the downwash ought to be very close to 0 (Zero)

though there is a wake.....

IMHO, CG is not the best way to deal with Yaw-Pitch coupling....
Moving the CG fwd will result in a Hz Tail or decalage trim to compensate... this
will prolly have negative impacts elsewhere.. such as the upline you just fixed....

I have also speculated that adding additional vertical area to the underside of the fuselage (Subfin)
could influence the yaw-pitch coupling.... Perhaps that will be a future investigation of the simulation
I am doing as shown below???