I have adopted the Matheson tartan because my great uncle is said to have worn a green kilt, aside from his old "regimentals" [a career military man, he fought in both world wars and retired as a sergent major in the 48th Highlanders]. The only green kilt that fit the description was the ancient hunting Matheson. The Stephen family [maternal ancestors] were long associated with the Mathesons, both in the Aberdeen area, and on the Isle of Skye. My great-great grandmother was a Matheson/Methieson/Mathieson [depending on which census or record you look at]. There are other clans and septs to which I probably have a connection, but I would rather determine that before wearing their tartan.
It has occurred to me that it would be quite wonderful to design a tartan to commemorate the 1000th anniversary of the recorded presence of the Stephens in Scotland. Other family names include Smith, Paul, and Chalmers, none of which seem to have a tartan associated with them.
I guess the long answer to the question of what colours one wears is that it is safest to go for those tartans that are most probably related to your family. Otherwise, google "interactive Tartan Weaver" and design your own. I think the cost is around $90.00 [Cdn] per metre for custom weaving, but something I'm considering anyway.