Since I made the capstrip spacers accurate, I go to the extra effort to make sure that the matching (front and rear) capstrips are using the same reference edge. In summary a master capstrip is used to drill one rear capstrip at a time. Then the rear capstrip is placed against a square reference edge so that the front capstrip will have the same distance to the reference edge.) The spacers can only be identical in length if extra care is made while drilling capstrips. Everyone has their own way of doing things. This picture is before capstrip is match drilled to spar. I put a couple of rivets in the holes thru capstrip. At this point there is no hole thru spar. I use rubber bands to hold capstips tightly against capstrip spacers. I then clamp and drill capstrips thru spar. When everything is assembled after anodize and painting everything will be in the exact location to be tight. the holes thru capstrip.