This discussion is theoretical for those who don't have a PS11. I often carry a regular sized iPad - not an iPad Air or an iPad mini (both smaller than my iPad) - in my PS11s
I carry wallet, phone, keys, sunglasses & small cosmetics pouch as well as the iPad.
I use a fold over clip on cover on my iPad - like a book binding - so the iPad functions easily.
I own PS11s but I couldn't imagine an ipad fitting until I read your posts! I suppose I will have to try it myself now.