With the 10-20 I find it best to use it how you did here if the sky is very dramatic and the subject. If theres a great sky I will have the sky take 2/3 of the pic.
If the sky is not amazing I will use the foreground things as subject
I don't think the sky is cool enough to justify 2/3s and you have nothing in your foreground so the pic falls alittle flat and without depth