Quink wanted to know how this worked, so I tried it today just to see.
The good news: it works, and the resulting coffee is much cleaner and clearer than with the standard Bodum filter disk.
The bad news:In my (so far fairly limited) experience, draining of vac pots with glass rods is somewhat slower than experienced with those with other filter methods. The Santos has a rather wider connecting tube than the Cona, and so the rod sits differently. I found that the draining time was extended (around 4 - 5 minutes for a litre) and so my coffee was somewhat over-brewed.
Verdict - a limited success. I'm not too clear what effect grind will have on draining times with both pots, but I'm going to try it and see.
Watch this space.