I used some CA glue to temporarily bond the lower extrusions in place while taking measurements. I placed the firewall onto the longerons to use as a straight edge and set all extrusions to 90 degrees of the longerons within .1 degree of accuracy. I've found my Clinometer app on my iphone is incredibly accurate and sensitive. HIGHLY recommend it to anyone not wanting to spend a lot on a digital level or lasers. Finally made a PDF of the drawing that will be sent to the engine mount fabricator.
