For my game, I decided to use Get Screen Width and figure out all of the devices, (there is a custom action I think for getting iOS device though), then I changed the camera's properties based on what device I'd detected.
E.g an FSM on the camera that checks the device, then branches off for each device, where I then use Set Property actions to modify the camera properties.
I also added some buttons on my front-end with Set Resolution attached, so I could switch between how the iOS devices would look but on a Windows standalone build, and then just tweaked the cameras until they looked better.