When you challenge a much stronger player should it be rated?

I feel that I can improve quickly by playing people who are better than me. That's why I've decided to send out some daily chess game challenges to high rated opponents. This may be a trivial question but is it better to send unrated challenges so they have nothing to lose, or rated challenges, so they know I'm serious about the game?

Unrated, unless is really low rated I wouldn't accept the challenge not because of fear but is because it isn't fair, once a beat like 10 times a 1500 player on blitz and lose 2 times against him and I end up losing points, so if I want to win some points I have to beat him 10 times and only lose 1 to win like 5 points, not fair at all

That makes sense, thank you for telling me.