When you hold the material in your hand, you will definitely notice the difference between light, medium, and heavy weight tartan. I have a kilt made of 11 oz fabric and one of 13 oz. It is surprising how much heavier the 13 oz feels than the 11 oz. I'm sure 16 or 18 oz material would be just as noticeably heavier than the 13 oz.

Consider the climate where you live. The more hot and humid the climate, the more I would suggest looking at lighter weight fabrics. The colder the climate, the more you'll want a heavier material wrapped around your body. Living in Florida and now South China, my lightweight kilt is wonderfully cool and practical. When I lived in Beijing, a heavier fabric was very welcome.

The general public will not notice the difference between a 5 or 8 yard kilt. But I can say that the way my 8-yard kilt hangs is far superior to my 5-yard one. The additional fabric and deeper pleats make for more swing and a more refined look overall. But the 5-yarder still looks very nice and I always get compliments on my kilt, no matter which one I am wearing.

Happy kilting!

Andrew