I get great results using an A7r II on a copy stand set up for back light using a strobe setup (Elinchrom Quadra) with several layers of white plexiglass for diffusion. I have an array of 35mm film stages: slip stage from a Forox, a pin registered film stage from a Marron Carrol, and a negative carrier from an Omega enlarger. I use either a WA 60mm Rodenstock Rodagon and/or an 80mm APO Rodenstock Rodagon N mounted onto a helicoid attached to extension tubes for the Sony FE mount (the ultimate lens for 1:1 dupes is the Rodenstock 75mm f/4 APO-Rodgaon-D).
The nice thing about this setup is that i can control the light output with the Elinchrom Skyport, focus in live view, and crank 'em out fast. The results are excellent. I think the 42 MP sensor is capable of out resolving most 35mm emulsions. It certainly out resolves photos taken on Tri-X, Plus-X, daylight Ektachrome, and color negatives. I cannot comment on Kodachrome 25, Panatomic X, T-Max 100, or Ektachrome Tungsten 50.
I shoot just a tad under 1:1. For larger format transparencies, any Oly with multi shot mode works well. However, it's a nuisance waiting for 8 exposures and it's a bit hard on flash gear. So, I only use that setup on rare occasions.
I like using the Elinchrom flash because it's extremely consistent. I usually set the white balance on the camera to 5000K. I also use a reticle for aligning the setup.
I was fortunate to purchase a Polaroid MP-4 XL copy stand on eBay in '06. It's a solid stand and versatile.