After reading The Kilt and How To Wear It, and then reading a post by Bugbear, I noticed that in both texts they talked about using a gold/yellow tourie on top of the bonnet. I found this to be interesting and have included the information below.

The first from Bugbear's post.

"He (Mr. Malcolm Macleod, the boat pilot) was now sixty-two years of age, hale, and well proportioned,--with a manly countenance, tanned by the weather, yet having a ruddiness in his cheeks, over a great part of which his rough beard extended.--His eye was quick and lively, yet his look was not fierce, but he appeared at once firm and good-humoured. He wore a pair of brogues,--Tartan hose which came up only near to his knees, and left them bare,--a purple camblet kilt,--a black waistcoat,-- a short green cloth coat bound with gold cord,--a yellowish bushy wig,--a large blue bonnet with a gold thread button. I never saw a figure that gave a more perfect representation of a Highland gentleman. I wished much to have a picture of him just as he was. I found him frank and polite,in the true sense of the word. (229-30)"

The from The Kilt and How To Wear It. Here he is refering to the idea that the red tourie is a symbol of loyalty to England. He also states the same with red waistcoats, that it might be better to use a yellow one.

"In any case, it might be well to avoid the mental friction arising from the possibility of countenancing or seeming to countenance notions of "English supremacy" by making ones "tourie" yellow instead of red wool, the former as everyone knows, the favourite colour of the Gael."

Just some food for thought.