Definitely your choice to make in terms of what salary you'd accept however I don't really understand the strategy of yours. I, or any US company, could just hire in the US if I was paying higher US rates. I could avoid the timezone issues, potential language issues, would be easier to get together in person if ever needed, etc. and I don't have to learn/concern myself with German employment laws.
All things equal, skills and such, I think it would be fairly easy to find a US based candidate at this price for part-time work. So why would I bother hiring from another country unless it saves me money?