I took down some vertical blinds to paint the room. Of course I couldn't find the mounting hardware afterward.

So...

A mount which clips arount the aluminium extrusion.

Set the extrusion width & height and other size if needed. Don't forget clearance for the window trim, like I did.

You need to check where the sliders are positioned and adjust to they clear the clip. Change extrAdjust which shaves the ends of the clip.

Optionally get M3-ish self tapping screws, short so they don't protude into space where the sliders go past. I have mounted the blind, the clip does hold well without screws.

I did 3 perimiters & 25% fill, seems pretty strong.