<I think the faces were
<hurried by Tiepolo,
<this is minor detail of
<the piece, I may take a
<little more time to
<detail the faces.

I do not think that Tiepolo actually "hurried" those faces, as you noted "this is a minor detail". If we take a look at the work of Michelangelo, the same "hurrying" in the secondary compositions (second, third, forth, etc. plains) would be present. The reason for that is that the human eye does not see all the details in focus at the same time, so the artist should reflect this factor along with the rules of perspective and foreshortening in the developing of the composition. If we look at any classic easel painting we will find that the faces and detail in the secondary plains are not as developed as the faces on the front plain. It is often overlooked in contemporary murals which results in the "cartoonish" (in ref. to movie) look of the mural.

Since you are painting this section as a separate panel as a study and not a copy, it is a good idea to "focus" the image a little. Just do not get carried away, it will change the look and feel of the painting.

Ilia Anossov
http://www.truefresco.com/anossov
http://www.truefresco.com/workshop