Ahhh....The fashion disasters of Harajuku. They go hand in hand with the freaks often found in Yoyogi park. And juxtaposed next to Meiji jingu,.....it'll make your head spin. You could wear your kilt there and no one'd notice.

Glad to hear there's a kilt in your future. I'll have to look up the Hunting Stewart tartan. Please post pics when you get some.

As for the technicalities, customs, conventions, and traditions;
I think that's really up to you to decide. Really there are no rules, and each family (not clan), and individual makes their own. If you've not been dressed in a certain tartan since you were a boy, and not regularly dress in a kilt, then you get to decide every aspect of your kilting. You then get to pass them on to your children, and a tradition is born. And in the future when your children visit X-marks, they'll be able to tell wonderful stories of celebrating O-shogatsu, and drinking sake, and enjoying sumo kilted, because that's their family's tradition.