Sorry what I forgot to make clear in my post is that to match in with the wedding party wearing tuxes with bowties and cummerbunds I would wear the Argyll jacket likewise with bowtie and cummerbund and not wear the waistcoat. I would only wear the waistcoat when the wedding party was likewise wearing waistcoats with their tuxes.

I actually have a white bowtie and a white vest and "Churchill collar" shirt to wear with my PC for white-tie-and-tails events.