The fastest way to get an iPhone 7plus is to search the inventory of Apple stores. That can be done very easily by using iStockNow Live iPhone 7 and 7 Plus Stock Map. Click on the lines on the upper right to search for the phone of your choice. Once you locate a phone in stock at a store close enough to drive to reserve it through Apple at Apple. Once all the available phone reservations are taken you have to wait until a minute past midnight to reserve your phone.
Hope this helps someone else. It's how I got mine.