I tried it the Friday I recieved the video but it didn't really work out at all and I was so disappointed I didn't even take any pictures! The bake and bond was so soft it wouldn't really sand at all.
Finally I found a moment to try again yesterday and baked them for much longer which has made them harder (and thankfully easier to sand) but I am still not happy with the results. I am posting some images here just in case anyone has cracked this technique can share some tips.
Here they are before sanding
I knew sanding was a key part of making these look good so I spent ages sanding one. Gave it a good long time at 180 and 240 grits and then went through 400, 800, 1000, 1500, 2000 and 2500 grits.
Here it is after sanding.
Not sure what caused the cracking on the bake and bond. My flake colours are still too bright but that isn't a huge issue on these cause you can't really see them.
I have reread some of the tips on Cindy's blog and I think perhaps I have some other ideas to try and also perhaps I ought to go back and sand some more. I will master this technique and hope to produce something closer to Cindy's beautiful sparkly faux opals!