Awesome! On potassium/tomato paste, wow, that is a novel idea. I would personally add it to this recipe, because cocoa + sugar + tomato sounds unpleasant, but I'm sure there are good savory recipes to be made with tomato.
[added and removed edit about Vitamin A]
Read the potassium information in the blog post, if you haven't already – one of the things I said there is that it's not the end of the world if you skip the potassium, because while 1.2 g (in the other ingredients) is unhealthily low, but relatively common in people's actual diets. So I'd recommend you try it without potassium, read all the safety information in the blog post, and optionally order supplemental potassium citrate/gluconate online.