Measure from the header to the floor to determine the door length you need.
How much overlap for barn doors.
The wall that the door rests on when it is fully open has to be at least the same width as one door.
Ideally the door will cover 2 to 3 inches beyond the opening on each side.
Measure from outside to outside of casing molding.
The picture above is of me seeing how the door will fit on the wall and how it will fit in the opening.
Add 1 to 2 per door for overlap depending on privacy needs.
Doors wider than 24 5 would work just fine but you loose access width when the doors are open.
Barn doors can be installed to overlap each other but it requires a different installation technique and barn door hardware which can increase cost.
Barn door measuring guide for door openings with casing molding.
The doors will need to be offset from each other on the track or sometimes even use an extra track.
Again for doorways with moldings measure from the top edge.
Measure across for the width and from the top of the casing molding to the floor for height.
Two 24 doors would not overlap at all and would not stay fully engaged into the center guide on the floor.
I used 7 6 slats which made my doors 42 wide and since my opening is 38 i was able to get 4 of overlap on the doors.
To figure out what size track you need double your final width measurement.