I know that when dave plays the song, during the main riff, he reaches to pick the E note on the 7th fret of the A string. However, I found it easier to hit the note on the 2nd fret of the D string. It's the same note, but since the next chord is D, which is located right there on the fretboard, I just found it easier to transition from that position. I know this is different than how dave plays it, but I'm just throwing it out there.
Random movie quote to make you seem hip and "with it": The food court is downstairs. The cookie stand is upstairs. It's not like we're talking quantum physics here.
Yeah, he slides from 5 to 7 so playing it on the d string would eliminate the slide thus changing the song noticeably. If you like the way it sounds, thats fine, but it might change the song too much for other people to play it that way.