I drilled the holes to #30 into the rear spar on all main ribs that did not have spacers. I placed and then drilled the ribs with spacers. I have all the holes in rear spar drilled except for those places in which you have to drill 2 additional holes. I used a bit of black tape along the spar to keep me from drilling from drilling what I should not. I also cleco'ed in place my aileron hinge brackets in place.
