It's all a rough estimate. I don't plan everything in detail, I allow myself to make some things up on the spot, which I believe allows for the story to develop organically.
The progress bar is mostly how close I 'feel' the update is to being done. I typically like to get in around 50 - 80 scenes per update, but that varies wildly depending on how big each scene is.
v0.8 should include somewhere around 60 scenes. Most story events in v0.8 are pretty huge. I've clocked some events in at 30 minutes each.
Ok. Seeing how most creators have a settup or a system of events when they make there games, it always seems repetitive. I happy too hear that you are making this title in a fairly un-used way. Obviously there is alot too think about when comming up with new feature or events, and I admire that with all that you have on your plate and being forced to come out with new updates, you are taking your time too make sure everything is correct and not crudely made.
If I would have to say anything about charecters, if possible I would be pleased to see kate become a new main character. (Thats just a thought and I understand that would be more work and make the game take longer).
Im sorry for the long text...