It really depends on what kind of tone you're trying to set that should determine what pov you use.

This being said, I've ready MANY a reader insert, and there are actually two different "second person point of views."

There's a second-first person pov and a second-third person pov from what I've observed.

The first one tells it an in "you," of course, but like first-person pov, it focuses mostly on the thoughts of the character that "you" are supposed to be. The second one uses the omnipresent, third-party type of narration that can kinda go into the minds of any of the characters in the plot, but is also less personal. Usually with reader inserts, what we see is the second-first-person pov, because it's the most involving.

Please note that I totally bull****ed those names....but nonetheless!

Past-tense is the easiest to work with and the most widely-accepted tense. Present tense is a little more difficult to work with.