I'm 6'0" and weigh 260 lb as well. It has been my experience in wearing kilts daily as my normal attire for the last two years, that a traditional (or traditional) style kilt looks much better worn at the natural waist (in my case just below the rib cage and about 3" above the navel). This is particularly true for us big guys. It makes us look slimmer and takes away the belly hanging over a belt. I wear 24" long kilts this way and the bottom of the kilt hits me right at the top of the knee.

The only time that I where pants is when I ride my motorcycle. I've done profile checks with my riding pants on vs. wearing a kilt, and my stomach is much more obvious in the pants.

If you are wearing non-traditional style kilts such as the Utilikilt or Amerikilt, these are designed to be worn more at the waist level where you would wear a pair of jeans.

I hope this helps. I'm sure some other guys of size will have some helpful info for you.

Darrell