Excellent work!
I've tried both fixed and zoom lenses for macro and actually like using my 12~60mm.
I know I'll catch crap for saying that from the macro purists out there but hey, photography is all about experimentation and keeping track of what works and what doesn't.
Also, I've found that using a zoom lens for macro and increasing your distance from the subject increases the focal plane and slightly increases DOF.
Here's an example where I used a zoom lens at a greater distance from the subject zooming in to frame the shot.
