Thought I had my mind made up on getting the ipad pro 10.5. But I really want to utilize the split screen option. Would the 12.9" be better? Some reviews says that the 10. 5" will only show the we second app in an iPhone screen side. Isn't that just the " slide over"? Can't I move the screen size for that app to the middle to make it "split screen"? Or would the12.9" just be a better choice to do split screen on? Also, if the 1 2.9 is the way to go, if I bought the 12.9 1st generation, and it had iOS 9, would it get the iOS 11 update?