Good point, Planet-LED (ex HDLED?, nice new hompage BTW
)!
The german shop Uhrcenter (link above) writes that the display size is 10mm x 36mm. This is obviously the crystal's size, not the display's, as the whole watch is only 36mm wide (without the "ugly bar").
Have a close look at the DZ7079 (leather strap), look at the display window's angle within the crystal: it is not correct! But it's the same angle as in the DZ7080 photo. Obviously the time display was copied from the DZ7080 photo to the DZ7079 photo, but because the watches were photographed at slightly different angles, it doesn't fit properly.
I think both images are photoshopped, because in reality the display is mirrored (at least the description tells this), so you'd just see the lit digits behind a mirror, but not a dark frame around them.
Assuming the DZ7080 photo shows the correct proportions, the digits are about 4.0mm high.
This is also true for the partial DZ7080 photo (with the blue display): the digits cover 40% of the crystal height, that is 4mm if the crystal has 10mm.
How much is 4mm? I've just measured the digit size of the red M-2 that I'm wearing today: exactly 4mm! I haven't ever heard of any complaints about the M-2's digit size
So at least the OLED digit's aren't tinier than other LED's digits.
Final note: the time and date display is said to appear in an "animated" way... No, I will definitley not buy this watch without the option to return it without cost.