Carried out this mod a few years ago, just got around to sharing it.
Fairly self explanatory. Hook stitched on to each corner to slot into the existing holes in the dash moulding.
Result, a nice tidy taught blind.
No one likes a saggy bottom (to their curtain!). My curtain is always sliding off the dash, so I'm interested.
Are the holes shown the ones that run along the dash, effectively under the wipers? They are the only ones I seem to have.