@Gedemon: Here's the cliffs.txt for the British main island and two small islands in the north. No idea if that's actually helpful to you atm.
It's a one line per direction code (multiple directions for some plots), please answer if this is the correct way for coding cliffs. Not that it's difficult but it's a ton of dry numbers work.
Before I do more (I would start with one continent at a time for the Giant Earth, the other maps would follow): Will it be possible to do this via worldbuilder (when released), or is coding inevitable? Sorry for skipping, if this has been already answered.