Just wanted to add that one food source of potassium that people might neglect is liver. I believe 100g of lamb or beef liver contains about 350mg of potassium, more than your average banana, and without the starch, although it does contain some sugar, in the form of glycogen.
Definitely worth having in the diet for non-vegetarians.
I read that 1 oz of lambs liver contains about the RDA of copper, and 1 oz of beef liver contains twice that much.
So if you have one 7oz serving of either, once a week, you should be ok for copper.
In addition, if you eat some muscle meat throughout the week, it's rich in zinc, and you should probably ok from a copper-zinc balance point of view. As always though, you are dependent on the soil where the animals were raised. If you know for sure they are from copper and/or zinc poor areas, then cautious supplementation might be an idea.