Adding gpu block, which setup?

[spixelspixel]

Going to watercool my gtx 670. Which of these layouts would be the best? I can only fit an additional 120 rad, either on the rear fan, or at the bottom of the case.


1 loop, 2 pumps
p1out -> 240 rad -> cpu block -> p2in -> p2out -> 120 rad -> gpu -> p1in

or

1 loop, serial pumps

p1out -> p2in -> p2out -> 240 rad -> cpu block -> 120 rad -> gpu block -> p1in

or

1 loop 1 pump

p1out -> 240 rad -> cpu block -> 120 rad -> gpu block -> p1in

or

2 loops 2 pumps