There are numerous threads on this subject (but I'm of no help finding them) and, I think, the consensus is: wear what you like. If you have an historical connection, pursue it. If you don't, wear the tartan/design you like, understanding that some are restricted (like a company's logo, as it were - someone may own the tartan and, as such, can restrict its use). The most important point would be to wear any tartan with respect.