Once the skins were in place on the skeleton, it was time to drill 4 rivet holes through the forward spar at the point where they join the spar, spar reinforcements (thick billet aluminum) and the forward and aft inboard ribs. This would test how well I measured/predrilled the inboard aft rib as well as my notches in the inboard forward rib. Image 2 shows the four holest....not bad! The right side turned out the same way.