Very well described, gaRCfield!!

I would add that the vertical location of the CG respect to the center of pressure created by the fuselage and the rudder may create a torque around the thrust axis that will add to the coupling effect.
Hence, moving the battery up or down, if possible, could help in a better KE.

Also, the highest the propeller thrust, the easier the KE, because of the vertical component; a propeller of bigger diameter and lower pitch would also help.

Regards!