I build for electric and need to keep things as light as I can. I build 40-60 sized electrics from kits and from plans. Light servos and RX help the most. I also use lightning holes and substitute balsa for ply aft of the wing. I build up the tail feathers instead of glueing those huge planks way out on the end of the plane. I build wingtips with formed laminated basswood and with electrics we never balance by adding weight we shift the power pack to get the proper balance. In fact I put RX and servos aft of trailing edge usually. I don't use a rudder much so I omit that servo too.