In your dooryard you can get away with closer spacing than you would do in a commercial venture. The spacing you have is what you will use. I have some trees within 10 feet of each other, not great but good enough if I don't mind reduced fruiting from parts of some trees. The alternative is the space well but graft 2 or 3 varieties on each tree. If you can get 4 or 5 varieties from 2 or 3 trees, you may be happy enough spacing them on 20 to 25 feet centers