Good tartan choice -- one rarely sees the Coburg tartan these days!

It's the same sett as Graham of Mentieth, but with purple in place of blue. This is also one of the tartans recommended for those of German heritage.

I really hope that when you get some clearer pictures of your kilt there is some green in there somewhere, though! From the pic you posted it looks all black and purple.

Here's the Coburg from the National Register...