Wow. I was about to start working on this for 5th edition.
I have already used the custom system builder to start playing a little, but to have it managing more stuff like phases and END, excellent.
Let me know if there is anything I can do to help.
I am a professional developer and have been working with JS, CSS, HTML since the 1996.
I am also a graphic designer and have been using Illustrator and PhotoShop since 1993.