Go as all out formal as you can - the Viennese are conservative and traditional.

There aren't many white tie functions in North America these days but there it is still alive and well.

Here's your chance to let them see what Highland Formal can be, because doubtless it's rarely seen. The two excellent threads showing escalating degrees of formality in highland wear should guide you.

I was the only kilted attendee at a Swiss formal function a few months ago and it attracted lots of appreciative comment. I expect you'll create a minor sensation, in the best of ways.

And yes - Murray would be my choice.