Hi Jim,
Good question. These are my findings as I have P4Pro and use iPad Pro 9.7". If I am using the new Go Pro 4 app, it has an enhanced video setting for the video feed. Very good and for my use I do not need a hood even when shooting Dog and flat style settings.
If I am using the Litchi app, shooting DLog, with flat style setting I have a very difficult time seeing what it going on the display. For use with the Litchi app I am strongly considering getting a hood.
One more thought. I also tried the new iPad that does not have anti-reflective settings. I thought the reflections coming off the glass made it difficult to use.
Hope this helps.
Don Barar