So it turns out that the local cocoa works great. I had been buying imported Hershey's cocoa for $8 a pound (at the very cheapest) because that's all I'd really found. Sometimes you end up buying something more expensive just because you know what it is.
But when we went to Abastos a couple of weeks ago asking for cocoa, we found some that was 75 cents a pound. We got a kilo, hoping it would be good and then we'd have a good stock, but it was cheap enough that it wasn't the end of the world if it was awful.
And it really is good. I've mostly made brownies with it which seems like a good test since the cocoa is so important in them. Another small victory. :)