Any advice on how I can improve my photography setup?

To each his own.

You have a very elaborate setup that really is complicated to me. Your purpose for macro photography is for artistic purposes and maybe that's the reason I don't get it.

From experience, all those work with slides in college, the camera uses the microscope as the lens. Aperture is controlled from the iris under the stage between the light source and the subject/slide. It has the added advantage of showing the effects on DOF live. To reduce shake we used a shutter release cable. We did everything in manual mode (we couldn't afford those black models with a computer chip then). Operation was normal as if it were a regular microscope. We simply used the camera as the eyepiece of the microscope and if we liked what we saw, whatever magnification it was on, we simply took a shot of it. What we did was purely academic, no artistic side to it, all technical.

Idk