First, welcome to Pro Cooling!
I have the same pump.
I don't have it set up yet, but I'm going a bit differant route. I want to preserve every drop of flow until it hits the CPU block. My set up will go like this.
Pump close coupled to the res with 3/4" copper tube to insure max low resistence flood of the inlet.
The pump outlet I'm going to turn 90 (Rotated on the pump head so it comes out level, NOT a 90 degree fitting on the outlet.) degrees and then run 3/4" copper to the rad which will also be very close to the pump. By close I mean a few inches (3?).
The rads outlet will go into 5/8" copper flexable line. This 5/8" line then goes to the CPU block.
The CPU outlet will go into 1/2" or 58" line to the GPU. The outlet of the GPU goes back into 5/8" line running back to the res.
The Iwaki's are expensive, so I want all the performance I can squeeze out.
The rad & it's fans, res & pump will all be housed in a small separete box that the main tower will sit on top of. The lines will run up into the tower through holes I'll drill for them. The idea is to keep them both as short and straight as I can, along with removing the heat from the rad, res and pump from the tower.
Should result in very low case temps with a minimum number of fans.
There is no way I'd waste any of the pumps flow with 3/8" ID lines. And if your lines are 3/8" ID think about what the ID of the barbs will be.
Not good.
But to each his own. Best of luck with your pump!
