John,
I think you'd be better off using a smaller aperture....f/6.3 is going to be limiting for you in shots like these. Push it out to f/11 or higher and you'll get a little more usable DOF.
My other criticism is a more personal liking.....it works better for me if the OOF part is beyond the main focus point, ie, the fly's head in focus with the OOF body behind it rather than having the OOF foreground.
Bob