>>11105872>how large would these islands have to be to support several citiesHow big are your cities?
Look at the Hawaiian islands. The big island has more than a few cities, and plenty of wilderness.
Do you want big cities, then look at Taiwan. Its only 250 miles long by 90 miles wide and is home to millions of people in several large cities, that like Japan, exist in river valleys because the island is a chain of mountains and those are the only flat places you could build a city. As a result you get a very interesting landscape where you've got a very big dense city within walking distance of steep mountains covered in dense forest.
You've also got the Caribbean if you want to look at another big group of islands with a much lower population density and lower flatter sandy islands. Puerto Rico has several large cities, and is home to a rainforest.
You don't necessarily need to make them scarce in resources, it all depends on the geology of your region.
Your ocean depth isn't that much of a big deal unless its shallow (which can warm up quickly and drive large storm systems). What is more important is where the ocean and wind currents are coming from. You'd need to build a coastline for your whole world, and its simple enough to figure out how things are going to flow by picking a direction for your planet to spin and extrapolate coriolis effects from that. Figuring out your weather patterns and trends from there is trivial and left as an exercise for the reader.
