Here is an example that works on iphone5 and all ipads (haven't tested it on iphone 4 though, it has a 3:2 ratio)
The WINDOW PROJECT is set to 1024, 768. It's a 4:3 ratio
So it's designed for the smallest resolution.
But the Layout size is designed for the bigger resolution. 768,1366 it's 16:9 ratio
So when the window will zoom out to SCALE OUTER the 16:9 ratio we won't see the white lines because the layout will be big enough to cover it.
However. If you don't use anchor behaviors on all your active and interactive game objects (don't use on moving objects though) all the positions will be changed because the screen windows is changing with the resolution (it's adapting from ipad to iphone5 screen). But if you put anchor behavior the relative position of all of your stuff would be conserved.
Notice the Layout size: 768,1366 it's 16:9 ratio. that's because the layout must to be big enough to fit the iphone 5 resolution screen. Ipad resolutions are relatively smaller. For 768p the 4:3 ratio of the ipad has 1024 instead of 1366, about 100 pixel white stripe!!!. So if you design your game for ipad it will run perfectly on it but will have white stripes issues on larger resolutions such as ipod ones. So ALWAYS DESIGN YOUR WINDOW FOR SMALLER RATIO/RESOLUTION BUT YOUR LAYOUT SIZE FOR THE BIGGER RATIO/RESOLUTION.
But if you look to the scroll to function you have (383, 683) -->actually it has to be 384, 683. Dunno why i wrote 383.
We want to scroll to the center of the screen may it be a 4:3 or 16:9 ratio or even 3:2. It will be approximatively in the center of Layout
To illustrate once more. I mentioned i haven't designed my game for iphone 4. (3:2 ratio)
So how will i do it? Simple!
I pick a window size compatible with 3:2 resolution (try to pick the nearest from 3:2, to 4:3 and 16:9 so distorsions will be minimal). Place your objects considering you have a 3:2 ratio game. Then anchor stuff. Make sure you layout is big enough to fit the bigger resolution and enjoy.
You will have to check that your anchor behavior worked well though. Sometimes you have to mess with settings.
Another alternative is pin to object. You create an invisible sprite with window's size and you pin stuff on it. But anchor is better.