+1 on the dual purpose servo. I did it that way in my F4J Phantom and SU-27. On the F4J, the distance to the elevons was fairly long so I used Golden Rod. Worked great. Not sure what your AUW is but the only thing that would concern me is using the 800 3S. Seems like you might need more gooo ! Mine fly with nothing less than 1800 mah but most of the time 2200mah. Just MHO. Looking good !