formal evening dress: vest or no?

[davidlpope]

I've had little occasion for formal kilting, so don't know one coat from another too well yet. In JSFMACLJR (MacLean Jr?)'s pictures we find Cluny MacPherson and MacLean of Dochgarroch both wearing what looks like the same kind of jacket at a formal occasion. What would be the name of that jacket?

I like tradition but also encourage modernity and forward thinking. I find I like the 5-button vest and also the jacket worn by the two Clan Chattan chiefs, but the PC - well, not so much.

Cluny is wearing a Regulation Doublet. I believe Dochgarroch is wearing a formal Argyle jacket.

David