"Could you please" vs "Could you kindly"

I am a non-native speaker of English. When communicating with a professor, would it be better to use could you kindly send me the document or could you please send me the document? I know both are correct, but which one shows more respect?

Solution 1:

Both are polite, and no reasonable professor would take objection to either. If you wanted to sound a little more formal, you could say I should be most grateful if you would send me the document.

Solution 2:

I would prefer the word please in more formal communications. Kindly would be better-suited for familiar environments.

Also, I would use the word "would" instead of "could."

Solution 3:

If your professor knows you're not a native English speaker, he should be happy with either of those. So the following is purely academic:

"Please" is always the politest word to use when making a request. It is never wrong.

To my British ears, the following phrases have a very slightly haranguing tone (as of a nagging mother):

Would you kindly ...

Would you please ...

Could you kindly ...

Could you please ...

Whereas "Please could you..." is straightforward, conventional, polite and ubiquitous.

Solution 4:

I prefer using kindly rather than please. The latter sounds more like begging.