The 747 argument makes at least 1 major flaw, making it a horrible comeback to the design argument.
1.God is outside of linear time. In other words the argument "who designed God?" is nonsensical, because it is literally asking "Who created the being that was not created?" God does not see time one day at a time. God knows all reality, from Creation on forever, in an eternal instant. He has no tomorrow, or yesterday, only "NOW". And His "NOW" encompasses all reality. Therefore unlike the universe, God does not require a creator, because He is eternal. Not eternal in the sense that He has always existed (in which case we could well ask "who created God", because we know all things in time require beginnings), but rather eternal in the sense that He is not in linear time at all, and therefore asking "who created God" is nonsensical, because since He is outside of time He needs no creator. Aquinas was teaching eternity before Einstein was born. As to your question about the idea of God being nonsensical, it is not. The reason people think Theology is stupid is because its almost always taught either by dumb people who don't understand it, or smart people who don't believe it. It is a leap in logic to think that because many Christians are stupid, that Christianity is false.
God is knowable. Those who say He isn't, lie. If God is outside of time, then He needs no creator, anymore than a circle needs a starting point. Because if God saw things one day at a time, then He would require a creator. Also, the Bible says so (WARNING: I absolutely hated having to say that) I do not mean that just because the Bible says it, it must be true, rather I mean that if the Christian God exists, He is outside of time, because that is how the hypothesis of God is stated. Also, the description of God is provable and disprovable. Also, the word "faith" has had its meaning changed. The modern "believe something without reason or evidence" is unbiblical. The original meaning meant "Something that isn't not perceived by the senses, but is still known by reason".
True, it is a statement. But one I am declaring is true. It was not intended as an insult. I knew when I was writing it that a circle was an imperfect analogy. I meant this. "Does a being completely outside of linear time require a creator or not?"
And to answer your last question. Deductive reasoning. I have never seen X (God in this case), but I have seen A, B, and C. If A, B, and C are true, then X must be true, even if X is not seen (or heard, smelt, etc)
I fail to see why God cannot be a transcendent super being, and a Father, Judge, and King. It seems to me Dawkins strikes a straw-man, attacking Yahweh as a kind of zeus, instead of as the being the Bible potrays.