Why would you be interested in an f2 lens if your interest is a wide depth of field?
Why would you be focus stacking and using VR?
I ask these because normally want a lens for macro to be sharp at the small apertures and have the camera on a tripod.
Hi Bob,
Small apertures to get more Depth of Field (DoF) come with a penalty of increasing diffraction blur. It's inevitable, it's physics.
Depending on the sensor it is used with, such a lens would probably offer its optimum quality at around f/4, and stacking multiple focused slices would allow extending the DoF zone at that aperture with higher quality than a narrower aperture would allow. It also offers the possibility to apply defocus blur to nearer and farther zones than the zone of main interest, by getting creative in postprocessing.
I am not a fan of focus stacking anyway. If you want to move a ton of dirt you don't use ten motorcycles.
Indoors at least I shoot at f18-20 with a mass of light.
Horses for courses, but at such short focal lengths, you'll already have lots of DoF, in addition to a wide Field of View.
As for the OP's question, what matters for focus-stacking to improve resolution in the focus-plane is lens quality at a given focus distance. I'm not sure that the lens mentioned is designed for its best performance at close focusing distances. It's more likely to be designed to be optimal at longer focus distances. So depending on what you want to shoot, start with the magnification factor that's needed for capturing the subject in whole. That will also give you the DoF, which basically just depends on magnification factor and aperture.
Maybe a shorter focal length, e.g. a Macro lens, will do better at the same magnification factor, although it will capture more (distracting) background due to its wider FoV.
If it is only resolution that you want to improve, you could try pano-stitching and downsampling. You can even do that with a narrower aperture since the downsampling will make the diffraction blur pattern smaller in output.
Cheers,
Bart