A 50/50 makes sense to me simply because it can't be cheated or there is no benefit to cheating. You earn the same for voting up your own stuff as you do voting for someone else.
What would happen in a 60/40 split or more would be alt accounts again voting for their own stuff. I see a 50/50 being the only fair and most rewarding system when I sit back and think about it.
As soon as there is even the smallest of edges to get more rewards in one direction they will come in droves.
Steemit itself could benefit hugely from this itself.
I have though about removing self votes but then again you still run into the same issue with alt accounts sadly. It's a real shame what people will do to try and game/cheat systems for pennies and it happens everywhere. It is why every social network that paid cash such as Yuwie, TSU etc all failed. You just can't give people free stuff without them abusing the hell out of it lol