I don't use the built-in save feature so I can't help you much there...However, you're generally better off not using the layout size at all - instead use a 9-patch or something to define the size and shape of the layout, use clamp() to keep scrollx/y within its boundaries, and enable unbounded scrolling. I guess you'd have to use the no save behavior with it too.
In the future you might consider using dictionaries/arrays to manage save data instead - you have far more control with them.
edit: Maybe you can place an object in each layout with 2 variables containing the width & height of the layout, give it the no save behavior, and set the layout size to them when needed. If you adjust the layout size later in development you'd also update these object's variables. *shrug*