New instant film back for Hasselblad 500, 501, 503 series cameras

The darkslide had classic sharp edges, burr edge, I very briefly touched the edges up with the first sandpaper I grabbed, 150 grit, will find some 400 and go over it again this weekend. Really hoping this thing works for checking lighting etc. Also just to make pictures.

I'm considering getting one to adapt to Bronica SQ-AI.
I've recently picked up a Polaroid back for the Bronica that I could possibly swap back plates with .

Does anyone here have both a Bronica SQ-AI and a Hasselblad 500 to compare backs with to see if shape and size are similar ?
Fixings would presumably be different, but that's why I picked up the Polaroid back to use .