Did I do this right? Dragonfly macro

[Outdoorsman]

Yes, it's already dead. I set it on a white sheet near a window and then cranked the aperture down as far as it could go with the available light. Then I fired a few hits from my flash unit off-camera (not connected) from overhead. It was a pretty dim foggy day, so the camera wouldn't let me get any more aperture. As it was, I set it to about f/27 or so. I think I could use a little more DOF, but who knows? Having never done it before, it was an experiment. I think I did okay. Any suggestions?
Elan 7N, Sigma 70-300, 2X converter, Provia 100F.