Steemit.com for example could present it as an option while writing a post:
Default (25% / 75%)
Reduced Visibility (0% / 100%)
More Visibility (50% / 50%)
Highest Visibility (75% / 25%)
I think it would be better to have a slider like SP voting slider from 1% to 100%.
The wider the spectrum the better imo. Someone who wants to keep say 95% of the rewards for himself should be able to do so as well.
The market for curation will become a lot more interesting with a wide spectrum. ( 1 to 100)
I think it'd be up to the frontend (whether steemit, busy, chainbb, etc) to decide if they want to give the users a choice. There's definitely benefit for some users - but it'd probably confuse others.
A good first step is even making it possible :D