Sure, first a voluntary donation selection with a percentage slider in the article formatter like how you can select your payout %, would probably earn quite a bit. I'd accept both Steem and Hive at first.
The other option would be to take a percentage of each article that's not voluntarty, like Busy and Dtube do.
I think these two are the most feasible to start right off, but of course prefer voluntary donation over a manditory fee.
Then we'd have to see how much it brings in and add more options if not enough.