As for 'requisite qualification' for God's existence, I shall attempt.
To be on a common platform with you, I am taking the liberty of assuming that you want to establish God scientifically and not through way of personal revelations or miracles.
No, you are 180 degrees wrong here. My position is that God will never, NEVER, be proven scientifically. Further I DO believe that God can be known via revelation; not only that, revelation is the ONLY way God may be known. Though I wholeheartedly agree that miracles in general cannot prove God. The one and only obvious exception is the miracle of revelation, of course.
You believe in science but not in God. If God exists, he would be the origin of science also. To become a scientist, you need to study science subjects. And that too under the able guidance of a professor. This process for acquiring knowledge of science is also applicable for acquiring knowledge of God, who is the fountainhead of all kinds of science and knowledge. This science of God is known as religion.
NO, I believe in science and God. I guess I'm coming forth here as a theist. No reason to be coy about it.

Of course you are correct that God would be the source of science. However, I disagree that a person must know the science of religion to attain sure knowledge of God. It's true that religious people are no less likely to experience God as a revelation than an atheist; but I believe that the God of the universe need not acquiesce to the religious beliefs of anyone, if God desires to reveal itself. No doubt, religion does contain many historical truths and useful, wise dictums to live by. However, to suggest as you do that one must seek God via that religion is shortsighted. The message of religion does not prove God, it presumes God, at least for us rational thinkers. In the absence of proof of God, those historical truths and dictums are the product of man's imagination. And what is that proof and where does it come from? I say that ultimately it comes to one via the gift of revelation, personally experienced. In the absence of such proof, Holy books like the Bible and Koran are nothing more than the product of man's toil.
Like you say, to experience God, He must make Himself known through some form of personal revelation. This revelation is there for EVERYONE - the revealed scriptures. Scriptures point towards God. But we have to WALK the TALK and not TALK the WALK. If anyone follows, God makes Himself known. If someone does not follow, all is mere dry MENTAL SPECULATION.
It's entirely possible that what you say here is true. One may be inspired to live in faith based on the Bible, the Koran, or any other "holy" book. This could in theory align their being with the divine, and could result in true knowledge of God in a revelation. Yes, I agree. But the Bible is not proof of God anymore than "War of the Worlds" is proof of martians.
The bible reveals; 'Thou shall not kill'. It is to be followed to understand the science of God. If I do not follow the injunction, and kill innocent animals to satisfy my taste buds, my efforts to seek God are futile. It is like God saying - 'you go east and you shall find Me'... and I choose to go west. Will I find God?!
Ostensibly I agree with you. Yes, I believe that one must walk a certain path in their search for the divine. However, if one remembers how much killing the war God of Canaan is guilty of , is not God itself the biggest violator of that commandment, "Thou shalt not kill"? It's difficult to count in the Bible the times that the God of unconditional love commanded the Jews to slaughter men, women, and children, and animals too, when mercy could have done so much more to prove to the world the Jew's special calling as God's chosen people.
Funny that we do not follow what God reveals to us, yet we want proof of God's existence. He is the Complete Whole, the Absolute Truth and Supremely independent. He does not need to prove His existence to us. God is not our order-carrier.
Nothing is revealed by God unless it is proven that God is the source of any text or knowledge. In the absence of proof, those works are the product of man's effort. The Bible, the Koran, or any other work is from the mind of man, not God, unless it can be proven without doubt that God inspired those works. And yes, God may be the "Absolute Truth and Supremely independent," but that truth and independence cannot be known irrefutably outside a personal revelation, I say. Whatever you believe the attributes of God to be, those attributes must be personally experienced to be known. Mere paper and ink, no matter what the content, will ever prove God. If you want a loving God, then that love must be personally experienced; if a forgiving God, then that forgiveness must be personally experienced; the power of God, then that power must be personally experienced. There is no other way. That's my contention.