I usually “collect” chocolate when it’s on sale at my groc—for example, this week, I can get two Green & Black’s bars for .97 each, so I got two and threw them in my freezer. Last week, it was BOGO on Ghiradhelli. So, for ganache, I use what I’ve got on hand, and I mix them (both brands and % cocoa), as well. It’s usually a combination of G&B, Lindt, and Ghiradhelli, but each is good on their own, as well. As long as your chocolate is “real” chocolate—not “baking bark”—it should be delicious. If you like the chooclate to eat, it should make a good ganache.
Your proposed ratio of chocolate to cream should make a good ganache for frosting a cake. You can also add a couple T. of liquor to it, if you want.