Quote - The black hole theory of infinite mass and zero volume per black hole isn't very logical IMHO.

Rationale:  How can the universe have billions plus black holes each with INFINITE mass?  There can be only one---hmmm heard that phrase somewhere---Jan 

Actually black holes don't have infinite mass. They have the mass of what-ever object
got mashed down to create them.  For example if a black hole was created by the
explosion of a large star in a super nova, the black hole would have what ever mass
of the star that wasn't blown out into space in the explosion.  In the centers of
some galaxies there are super massive black holes, but there the mass of those
black holes in just the mass of all the stars that clumped together to form it.
A micro-black hole would have a very tiny mass. 

But you are right about a black hole having zero volume, it is a singularity,
a single point in space with no width, height, or length.  You could think of it
as taking a Poser figure and setting the x,y, and z scale dimensions to zero.
It would still have all the vertices, but they would all be mashed down into a
single point that you wouldn't even see in a render.