This is almost the entire frame using a EF-25 II extension tube on a Canon XSi
18-55 IS kit lens with the focus set to give enough distance to the subject.

There is a trade-off between a shallow depth-of-field and unsharpness caused by diffraction.
Because the subject was large enough, I choose diffraction blur of f/29 over a shallow DOF.

Here is the macro-flash bracket (another view) rigged from a simple
flip-flash bracket with its hot-shoe attachment turned upside-down.