On the issue of tartan it is ABSOLUTELY VITAL that all Campbells interested in their clan be aware of one fact:
Most tartan or clan books have all the Campbell tartans wrong.
You are likely aware of this but few "overseas" i.e. non-Scottish native Campbells are aware of these facts:
Most books show something with (I think it is yellow and white stripes over the darker blue-green-black) called "Campbell of Argyll" as being the main tartan IT IS NOT authorized by the Chief. Anyone can wear it if you like it (as with all tartans) and if you have already been enveigled into spending good hard cash on it, our Chief says "wear it".
But the real Campbell tartan (and I knew only one other when growing up in Argyll in Scotland where my family have lived for about 600 years) is ONLY black, blue and green. You can also buy "Black Watch" which is the same but darker or "ancient Campbell" which is Campbell as described in the three colours above - or even "ancient Black Watch" which is exactly the same as "ancient Campbell" (or Campbell), but put out by the tartan companies as it is so popular and so that non Campbells can buy it.
The other Campbell tartan I knew as a child was Breadalbane which can be worn (as can regular Campbell called "ancient Campbell" by the trade) by those who descend from the Glenorchy-Breadalbane Campbells. And there is an authorised tartan for the Campbells of Loudoun and the Campbells of Cawdor.
Loudoun, Breadalbane and Cawdor are the three (originally)_ more important branches of Clan Campbell due to their national influence and subsequently being recognised with Earldoms. Normally only those who descend from one of those houses wear their special tartan. But in all cases what tartan you wear is a matter if courtesy; there are no laws. Since "clan" tartans as such only came into official being in about 1820, it is a relatively new way of designating your clan.
Finally a tartan called "Dress Campbell" is a good lumberjack pattern invented (some say) by L.L.Bean. So if you want the real McCoy (I mean Campbell) when buying Campbell tartan, go for "ancient Campbell" or Black Watch - in their variations (faded etc.).