Well, I always thought that the tartan was the centerpiece of the outfit and anything else patterned would be a distraction from it. Used to have an acquaintance that was a stand up comedienne that got a big laugh with a line about "mixing plaids"...certainly that would never happen with a member of Xmarks...though it might on a golf course or on a hipster.

Keep it plain and simple and let the tartan do the talking...ya' can't go wrong that way.

Best

AA