I recently experienced this quandry in my own life. Last Sat. I was getting ready for the Ligonier Highland Games and couldn't find the brown belt I was intending to wear (thank you, Mr. Murphy). I was wearing my MacDonald of the Isles Hunting weathered pattern and was planning to wear brown sporran & shoes. As we were running late (my daughter had to register to dance), I just decided to substitute a black belt that has a nice knotwork pattern & go. I was surprised at how well the overall outfit worked. I think the tartan helped to compliment rather than clash the colors. I even got a few compliments at the games. Next time i'd like to be better prepared ahead of time, but everything still worked out.