You can open any SGU/MGU file in different versions of Band-in-a-Box and on different computers. The OS only affects what version of Band-in-a-Box can be installed and not how the song project files are saved. The only thing to watch out for is that both versions have the same RealTracks installed that the particular song is using. For example if you make a song using an UltraPAK, then that song might be using RealTracks that a Pro PAK does not have.

The keyboard shortcut "Control + T" toggles between the classic layout and the modern layout of Band-in-a-Box. This can be done whether you are using a 13" inch screen or something else. You can also click/drag the edges of the window to re-size it, or switch to the DAW Plugin Mode to make the Band-in-a-Box window smaller.

Best,
Chantelle