You seem to have private messaging turned off, so this will be public, but less public than on the thread.
Tawna is insane and it doesn’t surprise me she hasn’t responded.
I did however speak with a friend who is also familiar with max and his offspring and we kind of both agree that your guy really looks too nice to be a max baby, especially the length of his back. Max was half saddlebred, quite long, and tended to throw quite long backed offspring.
You could try RPSI or American warmblood to see if any maxamillion colts matching yours were presented/registered the year of his birth.