I'd say that it is a great idea to show her the photos have her go through the Formal Wear Thread, the Best of your Best Thread, and the 10 looks thread, in this one look near the bottom for the appropriate dress, you may also get her to look at the vintage thread.

I would also say you should talk to her about how important your heritage is to you, also I would put forth the idea that the family tartan can pull together the entire decorating look for the wedding. At both my brother's weddings part of it was the presentation to the new bride of a sash in the clan tartan by my Dad. It was a symbolic welcome to the family and was very well received.