Completed match drilling aft edge of bottom skin to bottom spacer strip and cage tabs. Dimpled bottom and side skins for flush rivets that will be under the main gear mounts. Drilled holes in skin for landing gear mount bolts and brake line exit holes. Fabricated stringers for inside of bottom skin. Continued to fit firewall- the cage mounting bushings don't line up with the pre-drilled holes in the firewall when the firewall is square to the cage. Will keep working at this alignment.