I first had to recalculate the size of the bulkheads taking into account the thinner skin made of 3-mm aluminum rather than the 12 mm plywood as specified in the design.  The templates were cut of Mylar and clustered on 3 sheet of 3 mm aluminum.  Then notches were cut to allow the fitting of 25 mm angles to be used as longitudinal.

Aluminum Bulkheads