Staking my uncle

Hey, folks. This is my first post in the Zoo.

My uncle has been doing the Party play money SNGs and naturally dominates them. He wants to start at the 6s and I'm sure he'll quickly be able to move to 11s then the 22s without a problem.

I'm going to transfer $100 into his account. What do you consider the normal percent taken for a staking deal? I plan on giving him a steep "blood of my blood" discount, but we both agreed a stake is a stake and I should charge him something.

On a similar note, anybody else ever stake a relative? My uncle and I are pretty close, although he is more than twenty years my senior. Needless to say, I'm really getting a kick out of this.

Thanks.