For slide copy I use this setup as shown with the AI 55mm f/3.5 Micro Nikkor. This setup also works with any short FL lens that goes to 1:1. The setup involves A DIY double clamp from the PB-6 to the nodal slide. A simple, low price, IKEA LED light is convenient and perfectly OK. The color balance will be finetuned in post processing along minor retouching and final cropping. The old 55mm f/3.5 also works using the bellows part, not shown, as its FL is just long enough for 1:1. Also the bellows extension does not work against the CRC design which was not yet part of this lens. These days I mostly use the D7200 and the AFS 60mm f/2.8G with the double-clamp setup. 24Mpix seems quite enough. Yet on my next go at slide copying, I will cross-check against the D850.
I focus manually in LV, and by moving the slide rider, rather than by the lens focus ring.