A lot of people like movie series ‘box sets’ because they don’t have time or patience in an evening to watch a full length movie so I can see the logic.

But couldn’t you just watch about half of the film and then watch the next half another night?
I’ve done that before with the Extended Editions of LOTR, which came on two discs and so lent itself to taking a break.

For the original trilogy how about…
Stopping Star Wars after the Falcon takes off from Mos Eisley seems like a good spot.
Stopping ESB after Luke takes off from Hoth.
Stopping ROTJ after Jabba’s sail barge explodes.

I don’t see why it needs to get much more complicated than that?