Incidense and thrust
Make the thrust line and wing incidence easily adjustable. The final angles should depend in flight tests. If you start with everything at zero you can achieve a safe first flight by trim adjustment of rudder and elevator. The angle between the chord lines of the wing and tail (decalage) can then be adjusted to remove the need for elevator offset. The final decalage will depend on the CG location and the trimmed flight speed that you choose. The thrust line can then be adjusted so that the plane does not change pitch attitude much with changes in throttle or between power on and power off. Also, side thrust can be added so that rudder off set isn't needed. This proceedure is part of the proper development process of any new design and it even has to be done on well proven designs to accomodate pilot preferences for different CG locations and flying styles. It is really an essential part of flying any new model properly.