thoughts on red waistcoat with formal jacket?

[FossilHunter]

I'm aware that red waistcoats were pretty common historically but I was looking at the widely circulated photo of prince Charles at the state visit of Karl Gustav in 1975.



This is one of the only recent photos of someone wearing a red waistcoat formally that I can find other than one of that famous pipe major known for his flamboyance.

I like the look but wonder if it might be pushing the envelope of taste seeing as though the only two modern examples I can find are a man known for flamboyance and a royal at a state dinner. On the other hand, it doesn't seem as though it would be anymore flamboyant than a tartan waistcoat, and maybe even less so since it's a solid color.

I wonder what the rabble thinks? I am thinking that black regulation doublet with a red waistcoat would be quite smart.

One other thing though. Prince Charles waistcoat appears to be of the higher (maybe 4 button) style. Would that be more appropriate?