Maybe 20 blocks? It sort of depends, like if your building something like pixel art or making a simple small build, such as a generator of some sort.
Personally: Until the owner of the other island is comfortable. Check with a staff member and see if they can pull up when the owner of the island was last offline. Usually I check both in-game and on the forums for activity.
I think (If you are referring to island distances apart from one another) that korilla meant layers for one island, such as: ________ Top layer of cobble ________ Middle layer of coblle ________ Bottom layer of cobble Different building sections for an island.
Aah, in that case, I did about 12. I usuallly make a semi-convenient basement. Otherwise, I usually build up ^_^
I am 5 blocks away from another island and I really want it removed so I can build more Because the owner hasnt even started it
5 blocks away? And they have no built yet? That means you are definitely past the 100x100 limit, and if the island is reset by the owner and a part of your island disappears (likely to happen that close) then it will be your fault :/