When was the last time you used one of the garden areas? The east garden area is all reserved for the dessert party (all standing typically, especially now that capacity has been increased), and the west garden has a small section reserved for club level guests that booked extra FPs, and the rest is open and is all standing.
OP: I found the perfect spot during my past trip. In front of the dessert party garden area (Tomorrowland side), there is another rail enclosing a fountain. Right in front of that is where I stood. It is slightly elevated above the rest of the hub, so it is easier to see over the heads of tall people in front of you, and you have a rail to lean back on. I was able to walk up to this area about 20 minutes before the show 2 nights in a row and sit on the ground until about 5 minutes before the show started. Crowds filled in quite a bit once the show started, but it was still very enjoyable. I'm fairly certain there is an identical area on the other side of the hub as well, but they are pretty well centered to the castle so it is a great view.