I have never planted Dwarf trees, so I do not know the best spacing, maybe someone else here can help you. I would ask the people at the Nursery who sell them about size and spacing, they should be the experts.

Look for an Old Guy to talk with, I trust Old Guys a little bit more, they have already had their Learning Experiances, lol. The Standard trees along a fence or property line should be fine. I hope that they are on the North side, opps, you are down under, the South side of your yard. That way when they get tall, 40 to 50 feet tall, they will not shade the rest of the garden. That was one very good point that they made in the Ca video, they planted all of the tall trees on the North line, and came southwards with lower and lower trees so they did not shade each other out. That is a Good Idea to steal from them.

Never doubt that a small group of dedicated people can change the world, indeed it is the only thing that ever has.