I don't know the answer, but if you want to be close to the main pool, just ask MS to put that on your reservation. I'm sure the room assigners will do their best for you. Wouldn't hurt to arrive as early in the day as you can and repeat the request at check in.
Someone will probably post a link to the map or tell you which building(s) are closest to the pool, but it's best to request what you really want rather than specifc rooms or buildings. If the specific rooms/buildings aren't available the day you check in, the room assigner will have no idea what you really wanted or why you asked for what you did.
Best wishes -