If you are in the "Gimme Pain, Christian" part, you are almost done. The "Double the Pain" is just then ultra easy afterward. I just started a new line and have trouble getting my fingers sorted at the very first notes. And then there are two more lines* to learn. Takes some more time, but I must admit it sounds gorgeous - even when I play it. You know - pedaling makes the difference. But I can't practice for too long at a day, it is uncomfortable, and my ear gets pressure marks.
I took a look at your current sheet music and must admit, pedaling is quite difficult here. You must pedal down on eighth notes (with a tiny delay to let the previous eighths dampen silent), otherwise you hold dissonances, here and there.
*) with line I mean a 16 bar phrase, printed on an entire page on Christian's sheet music, 4 lines on my lead sheet to reduce everything onto two pages in total.
