Do I get more contributor exp if I add multiple keys?

No, you get the same cv. However, If you create more than 5 copies of the game, the cv will be reduced by 15%(if im not wrong).

I kind of fucked up by asking 2 questions. Which one did you answer?

It does not matter if you create a 5 copies giveaway or 5 giveaways with 1 copy each. You will receive the same contributor value.

Okay thanks

First off, you didn't reply directly to mugknight, so he can't see that you replied. You also didn't reply directly to Oppen, so he can't see that you replied, either.
Secondly, mugknight's answer was completely clear, and answers both your questions at once.
Oppenh4imer wrote exactly the same as he did, so I don't understand what the problem is with the first answer.
Also, the number is wrong. Additional giveaways beyond the 5th have their individual CVs reduced by 10% every time, stacking multiplicatively.
All of these answers, including mine, should be extremely clear. You can also read about the reduction in the FAQ.

Welcome to Steam Gifts. It's a valid question. I recommend you to look for keywords with the "search" option in the discussions for any doubt you have about how the site works. You can close this thread with the green "open" tab that's on your upper right corner when you're done.
GL & HF.