First of all Basso, there are not kilt police or Acts of Parliament to prevent you from wearing a Macpherson Tartan. As for morally wearing one, I guess that's between you and your maker. If you are up to it, maybe you could write to the Clan Chief of the Macphersons and ask his permission to wear his clan tartan, wouldn't hurt. A lot of people wear clan tartans that they have no affiliation with. If you do go with the Macpherson tartan, at some time you maybe asked why you are wearing it, just be truthfull and polite in your answer.

BTW Are you going to the Geelong Games on March 20, if so maybe a meet up is on?