I've been looking into the formal waistcoats and keep coming across silk waistcoats.

Any opinions about wearing the silk rather than the wool waistcoats with kilts?

While looking into this, I read, on a black tie attire advice site, suggestions that one should buy a black silk waistcoat rather than a wool waistcoat, if needing to add one to an outfit, because the black wool would never match the black wool of the jacket, and look mismatched.

Should I just ignore that advice and not worry too much about it?

Thank you.