I am well acquainted with both books you are referring and have observed the Duke of Rothesay as well as his great Uncle Edward (Duke of Windsor) with their pattern mixing panache. As Flussler says Edward could kick about in combinations that no mere mortal could concieve of.

If I have jacket on kilted or not I have a silk in the pocket, what other purpose does that little pocket have? It also "never" exactly matches the tie but compliments the tie or shirt or all of the above. I might add experimentation is key, I have had a few disasters that have not been repeated.

One final word, the arrangement in the pocket must look unplanned, almost an afterthought. Much the same reason I eschew a pre-tied bow tie because they are too perfect.

My compliments to JFSMACLJR and his stylish wardrobe and great examples of wearing a silk properly. To quote Tom Hanks in Apollo 13 as James Lovell "Gentleman this is how we do that". Well done!