There's really no real reason to get the other maps anyway even if they could spawn the Aquapolis since their drops are not that useful in the first place. I used to do the Wyvernskin ones frequently since they dropped materials I could use for weekly scrip crafting turn ins and could save me a bit of time. Now I max out on the dragonskin maps I can hold and then spend the rest of the week getting Wyvernskin so I can save the dragonskin for the weekend. It sounds like you just don't want to have to pick between the mariner cloth or the aquapolis?