ORIGINAL: dick Hanson

Yes a double taper or a cone or a ellipse etc', is highly desireable -and a stressed skin stab is the strongest -
I spent years designing models for competition flying- pattern/TOC/IMAC etc...
Most of the designs were far lighter than contemporary types -because THIS aspect of the design means far more than trying to figure what "airfoil" meant the most
basically -we found thru experience -in the sizes we work with - weight is 1,2 and three in the list of importance to getting best performance.
It follows then -that structural knowledge is the most important part of getting the model right the strongest lightest design is the best .
every time.
Try this:
If the model is light enough -the airfoil is meaningless
Once you understand this - you are on th track to best performance.