Your 8
apple trees sound great. You can make any pattern that you like. I would just match the varieties to your climate, and think you will not have any problem with pollination.
My trees are on the north side of the house, so they are in the shade all winter. I might have put them a little close together (4 feet) but they're fine. It is a moderate climate here and the winters are not very cold, so I planted anna, ein shemer, fiji, macintosh, golden delicious, and blenheim apricots.
I believe most apricots grow on last year's
wood, so it is important to keep some of last year's wood when they're pruned. There are many different ways to do this. Apricots are one of the most drought resistant fruit trees. I had a nectarine tree with delicious fruit but got over zealous with it at the start and it died. I am going to plant more of them.