Get out a tape measure....and you tell me if most all airplanes aren't based on the same BASIC set of parameters. You can't obfuscate the simple truth that they are.
Most airplanes are designed from a set of performance parameter demands. The designers take the requirements and start applying the formulas with the requirements included.
They're not designed "on a basic set of parameters". They're designed with a set of formulas.
And that's the truth.