D7200 with Micro-Nikkor 55mm F/3.5 Auto, a light table and a non-reflective glass plate.
I created an inverting picture control for scanning, it's nice to see what i'm getting! Shooting raw-files with the lens at F/8.
The end product. Fomapan 200 developed with Monobath df96. Shot with Nikon FE and Nikkor AI-S 50mm F/1.4. Re-sized to 4500x3000 pixels. That seems to be maximum resolution with my setup.
Looks good - and you are obviously producing good results. Some suggestions though..
Lights off elsewhere in the room (you may well be doing this already) and matt side of negative towards the camera (to reduce extra ious reflections and because the image is on that side of the acetate.
Raise the negative strip on blocks so that the light source is nowhere near the plane of focus - less chance of resolving a pixel (or dirt) in the light source.
Use a weight on top of the blocks to hold the strip flat, but try to avoid glass over the frame you are copying (any mark on the glass will be near the focus plane, plus you get reflections and may get Newton's rings).
To ensure you are square to the negative, place a mirror where the negative would go and position the camera so that the centre of the lens is centre of the frame - when it is you are square.
...but as I say, your results look good without that.