Due to space, we went with a combo. We put the composting toilet (yup, bucket and wood pellets) over the rear wheel well, so you have a step up to it after getting in the shower section. I cut a shower curtain to fit the window and the rest to fit over the step so it keeps the toilet area dry when showering. We use magnetic hooks for nearly EVERYTHING and so that makes it easy to put the 2nd shower curtain back on the wall side when done. We also opted to only have 1 sink because really? Do we need 2? And space, of course.
I pretty much shower when he's not home and he pretty much showers when I'm in bed but even when we're both home we've never had to both be in the bathroom at once. So far. *knock wood*
Editing to add that we have a drape that we use to create space. During the day it hangs against the closet. At night or when showering, we hang it across the hallway for privacy. The other drape currently hangs sideways across the windshield...