Ok so here is an update:

The original weight of the ribs W1-W2 was 4.8 oz, after drilling out the ribs as drawn they now weigh 3.3 oz. That is a savings of over 31 % in the weight of these 6 components. Originally the weight of the ribs for the wing panels would have been 6.8 oz, now we are looking at the component weight total being 5.5 oz I would not call that insignificant at all. Total time for drilling cutting and sanding was less than ½ an hour, not bad pay back, and just here I have more than compensated for the adding of two HS-81 servos for the flap function on this build.