Coupling Cap Types and Voodoo Parts?

[makinrose]

Hi Guys

Polester/mylar adds much more distortion than polypropylene, which is essentially distortion-free. Polyester adds odd-order harmonics which will be heard in different ways insofar as these harmonics become part of the input signal to the following gain stage, which distorts the fundamental and all these extra tones, so "fatter" is a possibility. The extent to which the cap distorts depends on the signal voltage across the cap.

If you want minimal ceramic cap distortion, use NP0 or C0G; for maximum grit use X7R.

Within a given dielectric range, the physical size of the cap will effect parasitic elements contributing to tone, as TUT3 states.

That  explains my affinity for polyester caps!  
 
The  line  that stuck out to me in TUT 3  was in 4-12 and reads " All that is required to make small parts sound like large ones, is an airy layout".  So what I'm inferring is that that state in conjunction with what you wrote on the post is that the parasitic elements are a function of layout (which is influenced by the size of the parts)  rather than the  size directly?

Which lead to one more question:  when you layout your amps are there rules of thumb that you use to ensure the spacing used minimizes parasitic element?