Large outdoor (sunlight) display

I have a project where I need to be able to display several numbers on a large display in direct sunlight.

I'm talking about 20 to 30cm in height.

Having done plenty of research and scouring these forums I think my options are:

electromagnetic flip dot display
electromagnetic 7 segment display
large LCD screen
E ink screen (perhaps several tablet size screens)

However I am struggling to find much information about using any of these.

Does anybody have any advice for these or other suggestions.

I'm particularly preferring a large E ink screen but how to interface with it seems difficult.