What engine for the Diablotin???
I just put one together with a Saito 91. With 2 elevator servos and the rudder servo in the tail it is still tail heavy.
I wouldnt use a smaller engine. If I was doing it again I would use the Saito 91 because I already had the engine but I would move the rudder servo forward in the fuse and use pull pull.
Joe Brannon