I have two Argylls-- one is a light grey tweed, the other black barathea. I have two waistcoats that I wear with my black Argyll (but not at the same time!). Both are black and one is a 3-button (as would be worn with a PC) and the other a 6-button (as might be worn with a three piece suit). If the event is "black tie" (ie: tuxedos) then I pop on the 3-button waistcoat and black bow tie and I'm off to the event. If it's a dressy day or evening event (when a conservative suit would be appropriate) I opt for the 6-button vest and a conservative striped tie. I only wear white shirts with the black Argyll, although I tend to favour light blue Oxford cloth button-downs with the tweed. I wear the same same conservative striped tie with the tweed jacket that I wear with the dressier Argyll-- it makes dressing much easier, and frankly I don't care if it tones with the stripes in my kilt. My life is more interesting that worrying about neckties!