I just got back from The Gathering in Edinburgh and chatted with several members of my Graham clan... Cameron Graham was wearing a fly plaid with his kilt jacket and it looked great! I had heard that it was not considered correct to wear it with the kilt jacket but he said he does it all the time. Since getting back, I've twice worn my fly plaid with the kilt jacket and it's received rave reviews... so I think it's fine! A small clan badge in sterling silver is a nice touch to hold the fly plaid to the jacket.