This is a very straightforward print. You’ll want to make the tube using opaque black filament. The spring film holder should be made of a neutral color to avoid imposing a color cast; I used white. If you decide to try printing the diffuser, use white or clear filament — but it is not necessary, and you might get more even lighting using a diffuse light source. I printed everything in PLA using 0.25mm extrusion and 25% fill. It uses well under 100 grams of material in total and prints quickly on my MakerGear M2.
The photos of Copenhagen are a scan that took 25 minutes using a Nikon CoolScan 9000 and the same slide photographed using a DupliHood on a Sony A7. Despite 80MP vs. 16MP active image area resolutions, the 80MP-equivalent 1:1 crops show the DupliHood image isn’t clearly inferior. This really can work quite well.
There are some issues in tweaking the design for your lens and in using the DupliHood — see my Instructable, instructables.com/id/3D-Printed-Slide-Copy-Attachment/ , for details.