I can tell if I am giving Scott a grand slam or a Home run by the way the person is talking about what they will do after the pool is build. If they are saying that it will be a great hang out spot for them, their kids friends and teammates, or that they can't wait to host again, it is a grand slam because their true goal is to build a space to host the people they care about and build memories with loved ones. 

For a home run, I would refer someone who is looking to build a pool in a space they have been told it is impossible to put one there