Help needed: Investing in Single vs Dual flash setup for macro

Ok, I thought I was linking the image, plus a clickable link to the page on my pbase site, which includes more info about the setup. Let me try that again.

Here is the link to the annotated image on my pbase site:

Pop-up diffuser for macro

And here are a couple of images for comparision. First, a shot I took with a dual-flash setup:

I'm pleased with that image, but note the harsh highlights in the eyes and in the dragonfly's "mouth." Also note the lack of shadows of any kind. Very unnatural looking light. Very clinical, dentist's office looking.

Then, look at this image:

Note how the highlights in that image are feathered on the edges and don't blow out the details of the insects. Also note the subtle shadow under the ants. The 3D shape of the ants is accented by the modeling of the subtly directional light, and it looks much more natural.

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Regards,
Duncan C
dpreview and PBase supporter.
http://www.pbase.com/duncanc/image/61499136/small.jpg
http://www.pbase.com/duncanc
My macro gallery:
http://www.pbase.com/duncanc/macro_pictures&page=all