I have completed the airframe and did a preliminary balance check with the O.S. 61 fx and hardware mounted. I thought the plane would need a lot of weight in the tail with the servo/receiver setup recommended in the manual. I tried moving the battery aft, and it was not enough weight ot make a significant difference. I decided to move the servos to the after portion of the fuselage. Hopefully I can update the group whether these mods were helpful or not.