I cut a couple of hinge pieces to mate up with horizontal hinges on the lower cowl, then drew a center line down them. I marked where the holes should go so that they will line up with the holes in the lower hinges. Then I center punched and drilled the holes to 1/16”. I inserted the pins and fit the upper cowl in place. Using a light inside the cowl, I drilled a 1/16” hole to verify location, then opened it up to #40. I was able to reach in and back up most of the holes with a block of wood when drilling. Got most of the holes on the right side done. On the left side I was able to use a light for the first 8 or so holes, then could not see a definite hole to drill into—besides I could not reach any further to back up with a wood block. I was able to get a couple of holes drilled to 1/16” near the aft end. Having a cut out for the oil filler door made the right side much easier. I removed the upper and lower cowl and clecoed the horizontal hinges to the cowls—at least all that I had previously drilled. I drilled out the remaining holes from the inside to 1/16”, then drilled #40 from the outside. I need to take apart and deburr, then re-install both cowl pieces and drill for three nutplates inside the nose. I am still in a quandary regarding how to exit and secure the horizontal pins in the front.