G'day Ed,
Sorry for the slow response... got home from work and am slowly working my way down the "to do" list.
The photos below show the repro demister vents fitted to an EK wagon. They are slightly too narrow for the dash slot, but that helps to shift them away from the wiper arm - as you can see in the photos, it's a tight fit but they (just!) clear with some judicious grinding on the drivers side.
The little plates that mount to the dash I made up from some gal sheet I had lying around... truth be known, you could almost use the bottom of an icecream container. The foam rubber helps it to seal. Both foam and rubber are Sikaflexed on.
The duct tape wrapped around the circular inlets is to adapt up to the dodgy blue pool hose... temporary until I find a decent source of long lengths of aluminium concertina hose.
Not a perfect bolt-up fit, but a lot easier than paying the $200-$400 per pair that original tin FB/EK vents pull on eBay.
Cheers,
Harv