Hence districts should be determined not manually, but through a certain rule that is agreed by both parties Nationally
[1] says there is already software to do this, and [2] gives a terrible example of a district in Pennsylvania.
[1] http://www.washingtonpost.com/wp-srv/special/politics/gerrym...
[2] https://www.washingtonpost.com/news/wonk/wp/2015/03/01/this-...
Oops. It's late here.
Unfortunately, as soon as you lay down some guideline, and perhaps a purely rational one, that puts one side or the other at a loss, you'll have objections to the rule.
I hate to say it, but I don't think your process solves anything and actually just adds complexity to the process. It probably makes matters worse.
Why do other parties not get a say?