[Spenner]

Since you are focus stacking then indeed light painting will be a problem. However, the fact that you can cleanly shoot at f/16 or even more permits you to have a way around that. What I mean by light painting is literally dancing a light around a high f-stop, low ISO exposure, highlighting whatever facets you are wanting to showcase, while in a dark environment. And then it'll pick up whatever the light has licked, so you can make it appear as though you have a much more elaborate light source (even using a flashlight or something can work as long as it's a pretty white LED).

It's only viable if you a have a solid rig but it appears you do :P anyhow just an idea if you feel restricted, but you are having solid results with what you're doing.