Do you mean 50% of your daily votes to yourself? If that's what you're working out with your delegator, then that's between the two of you. That's not something I would do though and I don't think it's very helpful overall. Why not just buy the stake yourself instead of renting it at high rates?
I have delegated stake. I've been using it mostly on others. I only post about 5 times per week on average and only rarely vote my own comments. When I do, its a low percentage. For my blog posts, I generally vote right around the same amount that I use on other posts...sometimes slightly higher. But again - I only post about 5 times per week, and two of those are contests where I give away the liquid rewards.
Even doing that, I'm making some very good returns. Upvoting myself at 100% while giving a small fraction of that to others would make me feel pretty dirty. I don't understand why people feel the need to do that, especially when they're using stake that isn't even theirs...that they didn't invest themselves. It just seems very cheap and greedy to me.