Think of it like a musical instrument. None are made without a lot of thought and using well known factors. The woods are carefully chosen, the thicknesses are a known factor on what quality of sound they produce. For example African Blackwood for the best of the clarinets, not just any piece of ABW, but the best pieces are used. Ever seen one made out of another wood? Maple for violins, again only the best is used by the professionals. They know the exact thickness to plane the wood to produce the "perfect" sound.
The same applies to most callmaking. The standards have been researched and researched over the years for how they are made, what are the best woods to use for what "instrument" you are working on. There has been countless hours of research spent over the years, some documented, some not. Many have tried to reinvent the "wheel", but it usually boils down to the same wheel is still the same old wheel just different treads....
Marvin