Before enlarging the holes for the camlocks, I first drill holes along the firewall and into the camlock strips that will allow the cowls to be clecoed to the fuselage,. The camlock holes will be too large to be used to hold the cowl tight as I don't want to install the camlocks now.
The extra holes will be filled during the finishing.
This is the center support strip with the silver clecoes in the extra holes and the camlock holes enlarged to the need size for the cowl side.



Here one of the screws (temporarily) in place.



The holes in the strips are the drilled too a larger diameter. On the left before drilling with the template in place, in the center after drilling and on the right with the receptacle in place.



The receptacles are riveted with countersunk rivets, so the strips have to be countersunk.


The same has to be done on the strips for the lower cowl. Some less work as the strips are straight.
On the picture you can see the three extra holes and the size difference of the holes in the strip and in the cowl.