What I use the clouds for is to generate the the shape of the landmass and for the lighting effects filter to have something to work with to make some mountains. So if you were going to cross-paste your base layer island you might also have to cut out a chunk of the clouds and paste them onto the other set of clouds. I don't remember how much Tear uses the clouds in his tut but if he doesn't use clouds for mountains then it's all moot and you don't have to cut the clouds layer at all, just the base layer. If there is any bathymetry (underwater topography) involved then you will need to cut/paste the clouds. Using the lasso tool with a fuzzines of 10 or more helps to avoid cutting hard line edges so that when you paste the new clouds you don't get any weird effects.