Log homes can be rather confusing and defy most conventional FEA programs. I don't know the exact situation you are reviewing but most walls have little moment on them because second floor/roof trusses bear directly on the wall with a simple pin-type connection. Your concern about buckling is...
I am taking the Structural I PE exam and would appreciate the advice of any PE's that may have taken it prior to their PE exam. Is it worth it? 4 days of review for $595 with no guarantee of passing.