I agree with bigtim that the two screws in the spar will not be a problem. Looking over some of my build photos, I noticed why you might want to beef up the ribs if your going to add aileron servo hatches. I had to move my flap servo hatches aft a bit because I modified the landing gear to retract in the scale position. This put the forward rail directly over a lightening hole in the ribs. To be on the safe side. I replaced part of the bit of die-cut wood that had been removed from those areas. This probably was unnecessary because I don't imagine that the aerodynamic forces are so great that the rib would break unless I belly landed with full flaps down and the flap hit a rock. That would be very unlikely because it's generally not a good idea to belly land with flaps in the first place.