I get what your saying, I'll give ultra soft a try on my computer. I've got a 980 so I don't see any problems arising. Making a smaller project is pretty much the same as making a movie. Let's say I made a 20 minute short and wanted to keep working on it, all of a sudden I have an hour long movie.
You need a clear start, middle and end. An opening gambit, something coming into the story to change it or characters driving the story in a new direction, and then an ending that is satisfying and makes sense with the rest of the film. You can't add 40 minutes to a 20 minute film and expect a good hour long film. You'd just have a 20 minute film and a 40 minute film tied into one title to make it longer (see: The Hobbit films.. haha).
I'm taking all you say into account, don't worry about that. I'm also very grateful for your advice, as it's good. Taking what everyone is saying into mind I might just make 3 parts to it instead. It would be the same length, just in parts. Everyone here says I should start smaller, so I'll take that into account and use this approach. This isn't me backing down, or making the project smaller. I'm not just going to make one part and stop, don't worry about that.
Respect! That will let you really fine tune the details of each release and also make it more accessible, two of the biggest concerns I had. This will be great :)