Finding the correct level of formality

[McMurdo]

I'd say that generally Robertson and Emma will just be glad that you can both attend. Looking at the photos of past years it seems that the level of formality is simply what the attendees can do, or are comfortable with. Having said that, if it were me I would wear the Prince Charlie, with the best kilt you have, I presume that would be the Black TFCK, I would wear it with a self tie bow tie. For the hose if you only have black it should be fine though it may look like you are wearing quite a bit of black, I would also wear the red flashes. The sporran you have sounds like it would be fine as well. Shoes I'd say wear the black lace up.

Another idea would be to look through the 1 kilt 10 looks thread .