First I fabricated the four small strips that will hold together the main bulkhead and the fuselage upper longeron, on the picture the two from the right side.



Then I rechecked the alignment of the firewall, the alignment of the weldments on the longeron and the distance from the main bulkhead. I had a small problem centering laterally the firewall, as I had drilled two holes a bit in a hurry. I moved the firewall (my plane will have two more rivets in this area), and drilled all the side skins.



Then I drilled the lower weldment, here is a picture from inside.