Way back in early 2020 I got in on a Kickstarter campaign to fund the production of an Instax mini back for the Hasselblad camera. In November of 2023 I finally received my back.
Hier is a video with my thoughts about it, as well as some advice for using it, avoiding issues, and getting accurate focus.
When measuring the distance, measure to where the back connects to the Hasselblad.
3d model for a spacer to go under the focusing screen (untested)
If someone has a 3d printer, you can try using this as a spacer. files below as .3dm and .OBJ
The height of the spacer is the key dimension, and as I don’t have a 3d printer myself I can’t test it out. I’m also not sure if the height will be the same on all Hasselblad models. For me 3.8mm was about right, another user said 4.3mm was good for him. So test it out and see what works for you.