Therefore, Jesus is God and man

Lutero:

... but faith can be beyond reason. We are called to be the "stewards of the MYSTERIES of God", not to make everything "reasonable" to our fallen, limited, sinful minds.

Very true. Faith can go beyond the ability of human reason to comprehend the Mysteries of God.

I'm not so willing to tell God what He CANNOT do....

Um, Jesus is BOTH 100% man AND 100% God AT THE SAME TIME.
BOTH. Fully. Completely. At the same time.

Absolutely! But God is Spirit. A Spirit can dwell in a material at any time. Therefore, Jesus is God and man. Two natures. Spiritual and material.

But can you show where two materials ever exist together 100% without affecting the size and weight of the object? You will not find that in Scripture or in science.

Jesus and Paul NEVER even mentioned "change." Anything changing from or two anything. 

The word they consistently and exclusively use is "IS"
IS has to do with being, existing, reality. It has nothing to do with "change."
When Peter and Thomas look to Jesus and proclaim, "My GOD!" that does not mean that He CANNOT ergo be human, that He has thus with the utterence of the words, undergone an alchemic transubstantiation leaving behind Aristotelian accidents of humanness OR that Peter and Thomas were speaking symbolically, metaphorically and Jesus is ONLY human.

That is true. But Transubstantiation is not used to explain the dual nature of Jesus. It is used to explain what Jesus did to the bread. Jesus said:

John 6:51

King James Version (KJV)
⁵¹ I am the living bread which came down from heaven: if any man eat of this bread, he shall live for ever: and the bread that I will give is my flesh, which I will give for the life of the world.

And Jesus also said elsewhere:
Matthew 26:26

King James Version (KJV)
²⁶ And as they were eating, Jesus took bread, and blessed it, and brake it, and gave it to the disciples, and said, Take, eat; this is my body.

Now, either that bread remained bread and also the Flesh of Jesus Christ, at the same time. Or that bread became the Body of Christ and appears to be bread but is no longer.

Since Scripture says:
Ephesians 3:10

King James Version (KJV)
¹⁰ To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God,

I believe the Church's explanation of Transubstantiation. 

Sincerely,

De Maria