1. 50/50 is not solution, we've been there, authors complained about it. We should not go in circles.
2. 30 minutes or 5 minutes - does not matter, because in worst case curator still loses. The point of this time period is to reward popular authors (which is fair), actual time parameter is secondary. I would not touch this one. It is working ok.

I like the proposal for 2018 roadmap where rewards split are set manually by author. Let market decide which proportion is good for any particular case. I would guestimate that something like 10 to author, 90 to curator will be natural choice for non-popular authors.