I'd give Matt Newsome a call at the

The Scottish Tartans Museum
86 East Main St
Franklin, NC 28734
(828)524-7472

tartans@scottishtartans.org

He might have some of the tartan on hand or be able to direct you to another source. Because of the time element I'd phone rather than PM.

If he doesn't have the proper tartan he may have something more approprite than black.

Most important is that you are getting married to the most beautify woman in the world - don't sweat the small stuff.

Best of luck.