[Lex]

I would recommend trial and error alleviate any fitting issues. Since you design without 3D, one need plenty of testing before settling on a developed shape. You can try tracing an untrimmed piece that is fitted onto your bulkheads rather than testfitting different trimmed pieces.

As to aerofoils, I *highly* doubt a truly symmetric aerofoil will be used in this day and age on a swept flying wing. You will normally find symmetric aerofoils on tail control surfaces and canards, but there are plenty of reasons to not do it on a primary lifting surface. Without knowing the exact aerofoil, I would suggest something like NACA2415 to get started. Don't be afraid to elaborate on your own, nobody is going to complain about not getting this correct.

The following image seem to confirm an asymmetric aerofoil with a much flatter lower surface. (also note the washout at the wingtip)
https://www.nytimes.com/2011/12/08/w...lance-bid.html