Suggestions on jackets ?

[Caradoc]

Think of the kilted equivalent of a tuxedo and a conservative business suit.

They're not implying, they're specifying; that's precisely what "formal" means in men's attire (personally, I'll pass on the frilly shirt in favor of a pleated one).

I, too, would pass on the frilly shirt.

This article describes the various levels.

"Formal," for me, generally means dark suit, tie, cufflinks, the works.

"Black tie" would be a tux.

I've never been invited to a white tie affair, so I don't know what I'd wear. Probably rent something in a tail coat, assuming I wasn't going kilted. Black Prince Charlie, white waistcoat, white tie, silver-and-fur sporran, and tartan hose would probably fit the occasion.