With my Saito .56 (15.5oz) I have the battery pack (1700 mah) mounted to the back of the former closest to the wing bolt down plate.. I think I may still be a tad tail heavy... I am going to tack a couple of ounce of lead in the nose and try it as soon as this weather straightens up.. As is the plane will tend to mildly porpise unless I am careful with the stick... This is sure a nice combo for some nice relaxing flying....