Last year I had a chance to see how in reality mast hound is fixed to the mast wall from the inside. Here is is the picture:
Before I enter the hound into the mast I apply 6 layers of glass biaxial 300g/m2. The purpose is to fill the gap between inner mast wall and hound. The result as you see is perfect. There are no air pockets and fit is as expected.
I will make a separate post on how to install a hound step by step.