Good point. I didn't think about grain direction reducing flex. I still however prefer built up over solid on anything with more then 1.5" of cord. Last time I fabricated some control surfaces it was for an old Hydeaway pattern airplane. I cut the surface outline out of 1/16 balsa, added a 1/4" thick leading edge of the correct height and a 1/8" carbon fiber rod for the trailing edge. 1/16 balsa sheet was use during for the ribs and diagonal ribs then sanded to the correct taper prior to the top 1/16 balsa sheeting. Light and stiff.