I usually play it on standard tuning as well. I'll have to try open G cuz that A shape can cramp my fingers after a while... For the ENDING riff, the previous poster is right. Hammer on 1234 while in between picking the strings (sometimes I go 2345 instead). I pick the G string personally. For the intro, to my ear, I hammer on 2324 with the pick of the G in between, but that 's just what I hear. Glad I'm not the only one playing this. I love to play this song, and my wife looks at me crooked because I play it so much. Such a great sound to it...